Adult Female Rats Research Articles

Betaine Attenuates The Expression of Vasoactive Mediators and Histological Alterations Associated with Ovarian Hyperstimulation Syndrome in Rats.

Ovarian hyperstimulation syndrome (OHSS) is one female reproductive disorder that can occur after administration of injectable hormonal drugs to stimulate ovulation. Betaine (BET) is an intracellular biomolecule with anti-inflammatory and tissue protective effects. There is no information about its effects in an experimental model of OHSS. The current study aims to investigate the possible effects of BET on abnormal expressions of vasoconstrictor proteins and ovarian histological changes in an experimental OHSS rat model. In this experimental study, 30 adult female rats (two months old) were randomly divided into six groups (n=5 per group): i. Control, ii. OHSS [10 IU sc equine chorionic gonadotropin (eCG) for 4 days followed by 30 IU sc human chorionic gonadotropin (hCG) on the fifth day], iii. OHSS+BET (200 mg/kg/day, orally for seven days), iv. OHSS+Cabergoline (CAB, 100 mg/kg/day, orally for six days), v. BET, and vi. CAB. Expression levels of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and blood levels of oestradiol (E2) and progesterone (P4) were measured at the end of the experiment. The ovaries were studied for histomorphological changes. Induction of OHSS altered tissue histology, including an increase in the number of corpora lutea and atretic follicles, and decreased the number of follicular reserves. In this group, we observed increased expressions of the VEGF and COX-2 proteins, and increased serum E2 and P4 levels. Administration of CAB and BET significantly attenuated all molecular and histological alterations observed in the OHSS animals. Our findings, for first time, indicate the beneficial effects of BET to reduce OHSS complications in patients by reducing the expressions of vasoactive proteins and improving changes to the ovarian tissues. The findings are similar to CAB and can be a new avenue for future research on BET.

Characterization of pain-related behaviors in a rat model of acute-to-chronic low back pain: single vs. multi-level disc injury.

Low back pain is the most common type of chronic pain. We examined pain-related behaviors across 18 weeks in rats that received injury to one or two lumbar intervertebral discs (IVD) to determine if multi-level disc injuries enhance/prolong pain. Twenty-three Sprague-Dawley adult female rats were used: 8 received disc puncture (DP) of one lumbar IVD (L5/6, DP-1); 8 received DP of two lumbar IVDs (L4/5 & L5/6, DP-2); 8 underwent sham surgery. DP-2 rats showed local (low back) sensitivity to pressure at 6- and 12-weeks post-injury, and remote sensitivity to pressure (upper thighs) at 12- and 18-weeks and touch (hind paws) at 6, 12 and 18-weeks. DP-1 rats showed local and remote pressure sensitivity at 12-weeks only (and no tactile sensitivity), relative to Sham DP rats. Both DP groups showed reduced distance traveled during gait testing over multiple weeks, compared to pre-injury; only DP-2 rats showed reduced distance relative to Sham DP rats at 12-weeks. DP-2 rats displayed reduced positive interactions with a novel adult female rat at 3-weeks and hesitation and freezing during gait assays from 6-weeks onwards. At study end (18-weeks), radiological and histological analyses revealed reduced disc height and degeneration of punctured IVDs. Serum BDNF and TNFα levels were higher at 18-weeks in DP-2 rats, relative to Sham DP rats, and levels correlated positively with remote sensitivity in hind paws (tactile) and thighs (pressure). Thus, multi-level disc injuries resulted in earlier, prolonged and greater discomfort locally and remotely, than single-level disc injury. BDNF and TNFα may have contributing roles.

Adolescent alcohol binge drinking and withdrawal: behavioural, brain GFAP-positive astrocytes and acute methamphetamine effects in adult female rats

RationaleAlcopop beverages are generally the first alcoholic beverage that young females drink which contain high levels of sugar and alcohol. The over-consumption of these drinks may encourage alcohol co-administration with methamphetamine (METH) impacting on drinking behaviour and glial function.AimsThe aims of this study were to evaluate the effect of adolescent binge alcohol exposure on consumption level, anxiety-like behaviour, cross-sensitization with METH and on astrocyte expression in reward related brain regions.MethodsAdolescent female Sprague-Dawley rats had daily 1-hour oral alcohol consumption of alcopop (ALCP; with sucrose) or ethanol-only (ETOH; without sucrose), transitioned from 5 to 15% (v/v) ethanol content for 34 days. Water and sucrose groups act as controls. During alcohol withdrawal, rats were tested for anxiety on the elevated plus maze (EPM) and locomotor activity following saline or METH (1 mg/kg i.p) treatment. Brains were then collected to assess astrocyte immunofluorescence for glial fibrillary acidic protein (GFAP) in reward-related brain regions.ResultsRats pretreated with 5% ALCP consumed significantly more volume and ethanol intake when compared to 5% EtOH rats. Both ALCP and EtOH groups had a higher preference ratio for 5% than 15% alcohol solutions and ALCP rats had greater ethanol intake at 15% than EtOH rats. Alcohol withdrawal showed no significant differences between groups on anxiety, METH cross-sensitization effects or GFAP intensity in the regions studied.ConclusionsOverall, the addition of sucrose to alcoholic solutions encouraged female rats to consume larger volumes and greater ethanol intake compared to ethanol-only solutions, yet did not have long lasting effects on behaviour and astrocytes.

The effect of olanzapine on spatial memory impairment, depressive-like behavior, pain perception, and BDNF and synaptophysin expression following childhood chronic unpredictable mild stress in adult male and female rats

Chronic unpredictable mild stress (CUMS) method has been introduced as a rodent model of depression. On the other hand, olanzapine, as an antipsychotic, can induce antidepressant and antipsychotic effects. Also, olanzapine may improve cognitive functions. Both CUMS and olanzapine can also affect the expression level of brain-derived neurotrophic factor (BDNF) and synaptophysin, the molecular factors involved in synaptic function, and learning and memory. In this study, we investigated the effect of olanzapine on locomotor activity (using open field test), pain threshold (using hot plate), depressive-like behavior (using forced swim test), spatial learning and memory (using Morris water maze), and BDNF and synaptophysin hippocampal expression (using real-time PCR) in both male and female CUMS rats. CUMS was performed for three consecutive weeks. Olanzapine was also injected intraperitoneally at the dose of 5 mg/kg. Our data showed that olanzapine can reverse the effects of CUMS on behavioral functions and BDNF and synaptophysin expression levels in the hippocampus of both males and females. It was also shown that olanzapine effects on spatial memory, pain perception, and BDNF and synaptophysin level were stronger in females than males. In conclusion, we suggested that the therapeutic effects of olanzapine in CUMS rats may be closely related to the function of BDNF and synaptophysin. Also, the therapeutic effects of olanzapine may be stronger in females. Therefore, and for the first time, we showed that there may be a sex difference in the effects of olanzapine on behavioral and molecular changes following CUMS.

Evaluation of the Protective and Healing Effects of Heracleum lasiopetalum Boiss on a Modified Acetic Acid-Induced Ulcerative Colitis Model in Rats

Background: Ulcerative colitis (UC), a chronic inflammatory condition of the colon with no definitive cure, necessitates the exploration of innovative therapies. Herbal remedies combined with conventional drugs may offer complementary benefits, enhancing treatment outcomes. Objectives: This study investigates the therapeutic effects of Heracleum lasiopetalum Boiss in a rat model of acetic acid-induced UC. Methods: Forty-eight adult female Wistar rats were randomly allocated to six groups (n = 8 per group) for each of two experiments. UC was induced by intracolonic administration of 1 ml of 4% acetic acid for 10 minutes. In the treatment groups, female rats received an oral gavage of 5%, 10%, and 40% aqueous plant extract, sulfasalazine (100 mg/kg), and distilled water for 6 days, starting 3 days after acetic acid administration. The protective groups received substances via oral gavage from 7 days before to 3 days after acetic acid administration. The extent of mucosal ulcers, hyperemia, inflammation, and mucosal bleeding was evaluated based on the Gerald Classification System Score (Macroscopic). Pathological assessment was conducted on prepared slides using the modified Wallace method (Microscopic). Changes in body and colon weight, along with food and water intake, were examined. Results: Significant changes in food intake were observed in both the extract and positive control treatment groups, exhibiting a notable difference compared to the negative control group (P < 0.05). Body weight changes experienced a significant increase in the positive control treatment group compared to the negative control group (P < 0.05), while no significant difference was evident between the extract and negative control treatment groups (P > 0.05). In terms of water and food intake, as well as weight changes, no significant differences were detected among the various protective groups (P > 0.05). Both microscopic and macroscopic examinations revealed a substantial enhancement in the colon of the extract and positive control treatment groups compared to the negative control group (P < 0.05), with no significant difference observed between the protective groups (P > 0.05). Conclusions: Heracleum lasiopetalum extract demonstrates a dose-dependent reduction in colon hyperemia, mucosal ulceration, inflammation, and fibrosis. This highlights its potential as a supplementary treatment option for UC, emphasizing the need for further investigation.

Topiramate treatment during adolescence induces short and long-term alterations in the reproductive system of female rats

Topiramate (TPM) is an antiepileptic drug used for treating epilepsy in children, and migraine in teenagers. In this context, preclinical studies with adult female rats observed reproductive system abnormalities following treatment with TPM. Additionally, exposure to endocrine disruptors during developmental plasticity periods, such as childhood and adolescence, may influence characteristics in the adult individual. This study evaluated whether treatment with TPM during developmental periods influences the reproductive system of female rats either immediately or in adult life. Female Wistar rats were treated with TPM (41 mg/Kg/day) by oral gavage from postnatal day (PND) 16–28, or PND 28–50, which correspond to childhood and adolescence, respectively, and euthanized either 24 h after the final administration or during adulthood. Treatment with TPM during adolescence induced short-term increase in uterus and ovary weights and reduction in endometrial stroma thickness. Adult animals treated during adolescence displayed reduced primordial ovarian follicles’ numbers, and increased primary and pre-antral ovarian follicles’ numbers. Treatment during childhood induced no short or long-term differences. These results indicate TPM treatment during adolescence is capable of inducing short and long-term alterations on the reproductive system of female Wistar rats.

Topical naltrexone increases aquaporin 5 production in the lacrimal gland and restores tear production in diabetic rats.

Diabetes mellitus is a prevalent disease that is often accompanied by ocular surface abnormalities including delayed epithelial wound healing and decreased corneal sensitivity. The impact of diabetes on the lacrimal functional unit (LFU) and the structures responsible for maintaining tear homeostasis, is not completely known. It has been shown that the Opioid Growth Factor Receptor (OGFr), and its ligand, Opioid Growth Factor (OGF), is dysregulated in the ocular surface of diabetic rats leading to overproduction of the inhibitory growth peptide OGF. The opioid antagonist naltrexone hydrochloride (NTX) blocks the OGF-OGFr pathway, and complete blockade following systemic or topical treatment with NTX restores the rate of re-epithelialization of corneal epithelial wounds, normalizes corneal sensitivity, and reverses dry eye in diabetic animal models. These effects occur rapidly and within days of initiating treatment. The present study was designed to understand mechanisms related to the fast reversal (<5 days) of dry eye by NTX in type 1 diabetes (T1D) by investigating dysregulation of the LFU. The approach involved examination of the morphology of the LFU before and after NTX treatment. Male and female adult Sprague-Dawley rats were rendered hyperglycemic with streptozotocin, and after 6 weeks rats were considered to be a T1D model. Rats received topical NTX twice daily to one eye for 10 days. During the period of treatment, tear production and corneal sensitivity were recorded. On day 11, animals were euthanized and orbital tissues including conjunctiva, eyelids, and lacrimal glands, were removed and processed for histologic examination including immunohistochemistry. Male and female T1D rats had significantly decreased tear production and corneal insensitivity, significantly decreased number and size of lacrimal gland acini, decreased expression of aquaporin-5 (AQP5) protein and decreased goblet cell size. Thus, 10 days of NTX treatment restored tear production and corneal sensitivity to normal values, increased AQP5 expression, and restored the surface area of goblet cells to normal. NTX had no effect on the number of lacrimal gland acini or the number of conjunctival goblet cells. In summary, blockade of the OGF-OGFr pathway with NTX reversed corneal and lacrimal gland complications and restored some components of tear homeostasis confirming the efficacy of topical NTX as a treatment for ocular defects in diabetes.

Effect of transgenerational diabetes via maternal lineage in female rats

AimTo investigate the transgenerational effect of maternal hyperglycemia on oxidative stress markers, lipid profile, glycemia, pancreatic beta (β)-cells, and reproductive outcomes in the F2 adult generation. Additionally, to expand the knowledge on transgenerational diabetes the F3 generation at birth will be evaluated. MethodsOn day 5 of postnatal life female Sprague-Dawley rat newborns (F0 generation) were distributed into two groups: Diabetic (Streptozotocin-STZ, 70 mg/kg body weight, subcutaneous route) and Control rats. Adult female rats from the F0 generation and subsequently the F1 generation were mated to obtain the F2 generation, which was distributed into F2 generation (granddaughters) from control (F2_C) and diabetic (F2_D) rats. Oral Glucose Tolerance Test (OGTT), the area under the curve (AUC), blood biochemical analyses, and pancreatic morphology were analyzed before pregnancy. Reproductive outcomes were performed at the end of pregnancy. At birth, the glycemia and body weight of F3_C and F3_D rats were determined. p < 0.05 was considered significant. ResultsF2_D had higher body weight, triglyceride levels, and percentage of insulin-immunostained cells, contributing to glucose intolerance, and insulin resistance before pregnancy. At day 21 of pregnancy, the F2_D showed increased embryonic losses before and after implantation (84.33 and 83.74 %, respectively). At birth, F3_D presented hyperglycemia, and 16.3 % of newborns were large for pregnancy age (LGA). ConclusionDiabetes induction since the neonatal period in the first generation (F0) led to transgenerational (F2 and F3 generations) changes via the maternal lineage of female rats, confirming the relevance of control strictly the glycemia all the time.

Chronic, episodic nicotine exposure enhances the hypoxic ventilatory response in adult female rats

It is well known that cigarette smoking causes lung disease and damages the airways. However, we know little about the direct role of nicotine, the primary addictive component of tobacco, in the development of smoking- related diseases. Along with promoting cancer cell proliferation and airway inflammation, nicotine can modulate central respiratory control, increasing the rate and depth of breathing through mechanisms that are not well understood. In addition, cigarette smoking is associated with obstructive sleep apnea, a sleep-related breathing disorder that is marked by reduced brainstem respiratory motor output. Despite these examples indicating that chronic nicotine exposure in adulthood may alter central respiratory control, there is no published research that directly tests this hypothesis. We exposed male and female adult rats to nicotine for four weeks through their drinking water and then used whole body plethysmography to test the hypothesis that chronic, episodic nicotine exposure alters restful breathing and the hypoxic ventilatory response (HVR), a critical respiratory chemoreflex. We measured tidal volume (TV) and frequency of breathing at rest, and during a 5- minute episode of hypoxia (10% oxygen/balance nitrogen). Total ventilation (VE/VCO2) was calculated as TV X Frequency and normalized to carbon dioxide production, to account for changes in metabolism, and body weight. For both males and females, comparisons were made between groups and across trials using a 2-way ANOVA and Tukey’s post-hoc test. In male rats, nicotine exposure significantly decreased overall ventilation at rest in one of three trials (Trial 1 VE/VCO2: Nicotine exposed, 30.7±7.5 mL/min/100g, Control, 44.3±6.4 mL/min/100g, p=0.0183), but had no effect on breathing during hypoxia. In female rats, nicotine exposure had no effect on breathing at rest, however, overall ventilation during hypoxia was enhanced in nicotine exposed rats compared to controls in two of three trials (Trial 1 VE/VCO2: Nicotine exposed, 106.8±20.6 mL/min/100g, Control, 79.8±5.1 mL/min/100g, p=0.049; Trial 3 VE/VCO2: Nicotine exposed, 101.6±9.9 mL/min/100g, Control, 68.1±10.9 mL/min/100g, p=0.007). Overall, these results suggest that chronic nicotine exposure triggers plasticity in the chemoreflex pathway mediating the HVR in a sex specific manner and further studies are warranted to understand the implications of this finding. 1K99HL164973-02. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Brain Derived Neurotrophic Factor (BDNF) Immunolabeling in C4-C5 Spinal Cord of Adult Female Rats Following Acute Intermittent Hypoxia (AIH) Exposure Composed of 5,3-min Hypoxic Episodes (AIH5x3min) at 4-weeks After mid-thoracic SCI

Acute intermittent hypoxia (AIH) induces spinal neural plasticity in both respiratory and non-respiratory somatic motor systems. AIH-induced neural plasticity has been best studied in the respiratory neural control system, where exposure to moderate AIH (9-15% inspired O2), typically composed of 3,5-min hypoxic episodes (AIH3x5min), has been shown to consistently elicit a robust increase in phrenic motor activity due to a serotonin-dependent mechanism that promotes de novo synthesis of BDNF and activation of high affnity BDNF-TrkB receptors to initiate ERK MAP kinase signaling in phrenic motoneurons. Whether other protocols that use a total duration of 15 min of hypoxic exposure, but with an increased number of shorter duration hypoxic episodes ( e.g, AIH5x3min) similarly elicit serotonin-dependent BDNF pathway-mediated neural plasticity mechanisms in this region remains to be determined. To begin to assess this possibility, we evaluated BDNF expression in C4-C5 spinal cord segments containing the phrenic motor nucleus following single exposure to AIH5x3min (12% O2) in urethane-anesthetized spontaneously breathing adult female rats at 4-weeks after mid-thoracic SCI. Experiments using AIH3x5min (12% O2) exposure and intermittent normoxia (Nx, 21% O2) exposure served as controls. At ~60-90 min after the AIH or Nx exposure protocol, the rats were transcardially perfused with saline followed by 4% PFA, and various regions of the CNS, including the C3-C5 spinal cord were removed, post-fixed, and cryoprotected. 20 μm thick transverse sections were then cut to obtain sets of slides for single- or double-label fluorescence IHC staining to localize BDNF protein expression in the C4-C5 spinal cord, including the region containing the phrenic motor nucleus. Preliminary analyses show that both AIH5x3min and AIH3x5min exposures elicit increased BDNF expression when compared to Nx exposure, with both diffuse cytosolic and punctate immunofluorescence labeling in and around neurons within the phrenic motor nucleus region, including labeling of presumptive phrenic motoneurons. No labeling was seen in adjacent tissue sections that were incubated without the primary antibody. Immunofluorescence labeling was also seen in the more medial regions of lamina VIII in the ventral horn, the medial regions of laminae VI and VII, and throughout lamina X; these regions have been reported to contain the V0-V3 classes of spinal interneurons (SpINs) albeit we did not verify BDNF labeling of specific classes of presumptive SpINs. These preliminary observations suggest that AIH5x3min exposure likely recruits a serotonin-dependent BDNF pathway-mediated mechanism for neural plasticity in a manner similar to that seen for AIH3x5min exposure. APS Summer Undergraduate Research Fellowship; DOD CDMRP W81XWH-17-1-0260; NYS DOH SCIRB C37711GG. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The progestinic drug, etonogestrel, rescues breathing in a rodent model of central chemoreflex impairment

The central CO2-chemoreflex is crucial in regulating breathing, providing stimulation at rest and during challenges to homeostasis. The retrotrapezoid nucleus (RTN), located in the ventral brainstem, is essential to this process. Impaired RTN function is linked to hypoventilation syndromes, including congenital central hypoventilation syndrome (CCHS) characterized by apnea and blunted responsiveness to inhaled CO2. Intriguingly, progestins stimulate breathing and CO2-chemoreflexes, and the high-affnity ligand etonogestrel (ETO) has been proposed as a treatment option in CCHS. Our objectives were to address two important gaps-in-knowledge: 1) assess ETO’s ability to “rescue” breathing in a rat model of central CO2-chemoreflex impairment, and 2) determine ETO’s site of action. We generated a model of CO2-chemoreflex impairment in adult female Sprague-Dawley rats using targeted injections of substance-P conjugated saporin toxin. Resulting RTN lesions were classified by the number of surviving chemosensitive neurons vs. non-surgical controls. We first administered systemic ETO (acute/vehicle:1h; or chronic/sham: 28 days) and measured resting ventilation and chemoreflexes (hypercapnia, 7.2% CO2; hypoxia, 10% O2) using whole-body plethysmography. In separate ongoing experiments, ETO was infused directly into target brain regions expressing progesterone receptors. We observed a positive relationship between lesion size and CO2-chemoreflex impairment (hypoxic response was intact). Twenty-one days of systemic ETO reversed CO2-impairment selectively in rats with moderate RTN lesions; large-lesion rats were refractory to ETO’s effects. These data suggest that ETO may enhance the CO2-chemoreflex by inducing neuroplasticity in brain structures with connectivity to surviving RTN chemosensitive neurons. Experiments are ongoing to parse out the site of ETO’s restorative action in the brain. T.A.J.:Canadian Lung Association BaO Fellowship, Canadian Institutes of Health Research (CIHR) Postdoctoral Fellowships. S.C.: Canadian Lung Association BaO Fellowship. S.P.: Women and Children’s Health Research Institute Innovation Grant, CIHR Project scheme grant. Nexplanon was kindly donated by Merck through the Investigator-Initiated Study Program (IISP # 55869; SP). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Dual-step pharmacological intervention for traumatic-like memories: implications from D-cycloserine and cannabidiol or clonidine in male and female rats.

Therapeutic approaches to mitigating traumatic memories have often faced resistance. Exploring safe reconsolidation blockers, drugs capable of reducing the emotional valence of the memory upon brief retrieval and reactivation, emerges as a promising pharmacological strategy. Towards this objective, preclinical investigations should focus on aversive memories resulting in maladaptive outcomes and consider sex-related differences to enhance their translatability. After selecting a relatively high training magnitude leading to the formation of a more intense and generalized fear memory in adult female and male rats, we investigated whether two clinically approved drugs disrupting its reconsolidation remain effective. We found resistant reconsolidation impairment by the α2-adrenergic receptor agonist clonidine or cannabidiol, a major non-psychotomimetic Cannabis sativa component. However, pre-retrieval administration of D-cycloserine, a partial agonist at the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor complex, facilitated their impairing effects on reconsolidation. A similar reconsolidation blockade by clonidine or cannabidiol was achieved following exposure to a non-conditioned but generalized context after D-cycloserine administration. This suggests that sufficient memory destabilization can accompany generalized fear expression. Combining clonidine with cannabidiol without potentiating memory destabilization by D-cycloserine was ineffective. These findings highlight the importance of NMDA receptor signaling in memory destabilization and underscore the efficacy of a dual-step pharmacological intervention in attenuating traumatic-like memories, even in a context different from the original learning environment.

Sex-Specific Mitochondrial Bioenergetics Differences in Heart and Kidney Cortex

Rationale: Mitochondrial bioenergetics of different tissues have been studied widely, but their sex-specific differences have not been systematically studied. The goal of this study was therefore to investigate the sex-specific differences in mitochondrial respiration (oxygen consumption rate; OCR) and membrane potential (Δψ) in the heart and kidney cortex and to explore underlying mechanisms responsible for any observed differences. Methods: Mitochondria were isolated from adult male and female Sprague-Dawley rat heart and kidney cortex and were used to study their bioenergetics responses. Three different substrate combinations, namely, pyruvate+malate (PM), glutamate+malate (GM), and succinate in the presence of complex I inhibitor rotenone (SR) were used. This was followed by two different ADP addition protocols to determine how different substrates influence mitochondrial OCR and Δψ to ADP perturbations during oxidative phosphorylation (OxPhos) in male and female heart and kidney cortex. In one, a single saturated dose of ADP, while in the other, sequentially increasing doses of ADP were added to mitochondria in the presence of different substrates. Mitochondrial OCR was measured using a dual chamber Oroboros Oxygraph-2k Instrument and Δψ was measured using a spectrofluorometer and rhodamine-123 dye. From these measurements, OCR and Δψ alterations under different respiratory states and as functions of added ADP concentration were determined for different substrates and for both male and female rats. Results: Male and female mitochondria exhibited distinct respiratory patterns in the kidney cortex and heart with different substrates. In the kidney cortex, male mitochondria showed significantly higher OCR than female mitochondria when fueled with PM or SR. However, no significant sex differences in the OCR were observed when GM were used as substrates. In contrast, heart mitochondria exhibited negligible sex differences in the OCR for PM and SR, but significant differences emerged with GM, where female mitochondria displayed higher OCR than their male counterparts. Interestingly, sex-specific variations of Δψ in ADP-stimulated respiration were not apparent for either tissue or substrate when a single saturated dose of ADP was used. Instead, a trend similar to the OCR emerged when ADP was administered in gradually increasing concentrations. Conclusion: Heart and kidney cortex mitochondrial Δψ for males and females did not differ conclusively with the two ADP addition protocols. However, there were significant differences in the OCR of mitochondria from the heart and kidney cortex of males and females, depending on the respiratory substrate utilized. Males were found to have enhanced OCR in the kidney cortex, whereas females exhibited higher OCR in the heart. These observed sex-specific differences in the OCR could be attributed to differential regulation of mitochondrial metabolic pathways by respiratory substrates and sex hormones. NIH R01-HL151587. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Does ovariectomy exacerbate the cardiorespiratory and metabolic consequences of moderate intermittent hypoxia in female rats?

Intermittent hypoxia (IH) is a major consequence of sleep apnea (SA). IH causes respiratory dysfunction and contributes to numerous co-morbidities of SA including hypertension and obesity. The fact that menopause increases the prevalence of SA and related diseases in women indicates the importance of loss of ovarian function in the pathophysiology. Here, we determined whether experimental loss of ovarian function (ovariectomy; OVX) exacerbates the cardiorespiratory and metabolic consequences of IH. We explored neuroendocrine changes by assessing hormones known to be involved in energy balance, respiratory control, and stress responses (leptin, ACTH and corticosterone). We subjected adult (8 weeks) Sprague Dawley female rats to bilateral OVX (n = 13) or sham operation (n = 14). Rats were housed in pairs, and after two weeks of recovery, animals were exposed to room air (control; n = 16) or to a 7-day moderate IH protocol (n = 11). Within their cage, rats intermittently received a nitrogen-enriched hypoxic mixture, followed by room air for reoxygenation. Each bout of hypoxia lasted 30 seconds (nadir FIO2 = 0.10) and was followed by 5-minutes of reoxygenation (10 cycles/h, for 8hrs between 10h-18h). Apnea frequency, acute responses to hypoxia (FIO2 = 0.12; 120 sec) and hypercapnia (FICO2 = 0.05; 10 min) were measured by whole-body plethysmography. Blood pressure was assessed by the tail cuff method, and body weight was followed throughout the protocol. Plasma corticosterone and leptin were measured by multiplex assays. OVX increased apneic events, whereas IH reduced them; with the highest frequency observed in OVX females maintained in normoxia. Ventilatory responses (hypoxia and CO2) and blood pressure were not affected by IH or OVX. Over the course of the protocol, OVX increased weight gain whereas IH induced weight loss. OVX (but not IH) increased ACTH and corticosterone. IH (but not OVX) reduced leptin. Correlation matrix analysis showed that weight gain was the best predictor of apnea frequency (r = 0.759; p = 0.03). We conclude that loss of ovarian function and related weight gain have the greatest impact on respiratory function during sleep. Additionally, OVX-related activation of the stress pathways may contribute to this process. These results fail to demonstrate a role for OVX in exacerbating the cardiorespiratory and metabolic consequences of IH. Lack of weight gain following IH likely contributes to this finding. This study is supported by operating grants from the Canadian Institutes of Health Research (RK and VJ). NJM is supported by a Sentinel North Partnered Research Chair in Sleep Pharmacometabolism and a Canada Research Chair in Metabolism and Sleep Neurobiology. MG received a doctoral scholarship from the Fonds de Recherche du Québec — Santé (FRQS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The multi-omic response to exercise training across rat tissues: interactive tools for data dissemination through the MoTrPAC data hub

The Molecular Transducers of Physical Activity Consortium (MoTrPAC) aims to map the molecular responses to exercise and training to elucidate how exercise improves health and prevents disease. The first MoTrPAC data provides an extensive temporal map of the dynamic multi-omic response to endurance training across multiple rat tissues. All results can be viewed, interrogated, and downloaded in a user-friendly, publicly accessible data portal ( https://motrpac-data.org ). The MoTrPAC data compendium includes transcriptomics, proteomics, metabolomics, phosphoproteomics, acetylproteomics, ubiquitylproteomics, DNA methylation, chromatin accessibility, and multiplexed immunoassay data. This compilation of 211 datasets across 19 tissues, 25 molecular assays, and 4 training time points in adult male and female rats constitutes 19 terabytes of data. Over 35,000 analytes were found to be differentially regulated in response to endurance training, with many displaying sexual dimorphism. We observed a male-specific recruitment of immune cells to adipose tissues and an anticorrelated transcriptional response in the adrenal gland related to the stress response. Temporal multi-omic and multi-tissue integration demonstrated similar temporal responses in the heart and skeletal muscle, reflecting a concerted adaptation of mitochondrial biogenesis and metabolism. Integrative multi-omic network analysis revealed connections between the heat shock-mediated stress response and mitochondrial biogenesis. Training increased phospholipids and decreased triacylglycerols in the liver, and there were extensive changes to mitochondrial protein acetylation. Many changes were relevant for human health conditions, such as non-alcoholic fatty liver disease, inflammatory bowel disease, cardiovascular wellness, and tissue damage and repair. Altogether, this MoTrPAC resource provides an unprecedented view of the effects of exercise across an organism, revealing mechanistic details of how exercise impacts mammalian health. The MoTrPAC data hub is the primary online resource to disseminate this large scale multi-omics data. The MoTrPAC Study is supported by NIH grants U24OD026629 (Bioinformatics Center), U24DK112349, U24DK112342, U24DK112340, U24DK112341, U24DK112326, U24DK112331, U24DK112348 (Chemical Analysis Sites), U24AR071113 (Consortium Coordinating Center), U01AG055133, U01AG055137 and U01AG055135 (PASS/Animal Sites). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ethanol pre-exposure attenuates the hypoxic ventilatory response and may attenuate expression of long term facilitation following intermittent hypoxia treatment in adult rats

Obstructive sleep apnea (OSA) is a highly prevalent breathing disorder in which airway collapse or obstruction during sleep leads to periodic bouts of inadequate (hypopneic) or absent (apneic) ventilation despite neurorespiratory effort. Repetitive apneic and hypopneic exposures during sleep can induce intermittent hypoxemia, sympathetic activation, and sleep fragmentation which can lead to a host of maladaptive behavioral and physiological outcomes. Intermittent hypoxia, which consists of alternating exposure to hypoxia and normal oxygen levels (normoxia), can induce a long-lasting increase in breathing motor output called long term facilitation (LTF) and is currently being investigated as a therapeutic treatment. Interestingly, experts in the field of LTF have noted how IH models some key aspects of OSA. It has been well established through clinical studies that ethanol consumption prior to sleep exacerbates existing OSA, increasing the apnea/hypopnea index and worsening arterial blood oxygen desaturations during the night. However, it is unknown whether ethanol affects expression of LTF following IH treatment. If LTF might serve as a means of increasing ventilatory output to compensate for periods of apnea and hypopnea during OSA, ethanol might not only worsen the severity of OSA, but impede individuals’ compensatory response. Thus, for this study we hypothesized that ethanol treatment would attenuate LTF expression and the magnitude of the hypoxic ventilatory response during IH treatment. Using adult female Sprague-Dawley rats, we administered either low-dose (0.8 g/kg) or high-dose (3 g/kg) ethanol through intraperitoneal injection to model a 2-drink nightcap or binge drinking-type ethanol exposure, respectively. Immediately afterwards, we measured subjects’ ventilatory output during baseline, then during a 5 by 3-minute moderate IH protocol, and for one hour following the end of IH using whole-body plethysmography. Finally, we took venous blood samples to assay serum ethanol concentration at the end of the approximately 2.5 hour plethysmography measurement. Results from the high-dose ethanol group indicate that ethanol pre-exposure might attenuate respiratory rate and minute volume LTF in comparison to saline-treated control. Furthermore, high-dose ethanol attenuated the hypoxic ventilatory response with respect to respiratory rate and minute volume. Low dosage of ethanol attenuated subjects’ HVR of respiratory rate and minute volume, but conflictingly trends towards increasing LTF of tidal volume while diminishing LTF of respiratory rate when compared to saline control. Overall, our findings indicate that high levels of ethanol exposure dramatically diminish the acute ventilatory response to hypoxic exposure and may impede long-term increases in ventilatory output following IH treatment. On the other hand, lower doses of ethanol have a subtler effect on the ventilatory response to hypoxia. Future directions will include analysis of additional parameters of ventilatory function to gain a more detailed understanding of how ethanol effects respiratory plasticity in the context of intermittent hypoxic exposure. NIH 5T32 AA027488 to ALSUniversity of Kentucky Endowment to WJA. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Inspiratory Neural Network Complexity Quantified by Approximate Entropy (ApEn) Analysis in SN 6-OHDA-induced Rat Model of Parkinson’s Disease

Parkinson’s disease (PD) is a multifaceted chronic and progressive neurodegenerative disease that includes a broad range of motor and non-motor symptoms (NMS). Breathing abnormalities are a common NMS in PD, and despite respiratory dysfunction being a major problem in PD as well as respiratory complications being the most common cause of death in PD patients, this NMS receives little attention. Over the last decade, a number of preclinical experimental rat models of PD generated by nigrostriatal site-targeted administration of the neurotoxin 6-hydroxydopamine (6-OHDA) have been used to evaluate various aspects of ventilatory control in PD. While all of these models have been shown to exhibit basal and chemical control of breathing abnormalities that are consistent with those in clinical reports, no studies have assessed the complex intrinsic dynamics that are associated with the central inspiratory neural network in PD. Since preclinical rat models of PD have also been shown exhibit neuroanatomical changes in brainstem regions involved in ventilatory control, it is likely that changes in inspiratory neural network dynamics, which can be assessed using nonlinear dynamical analysis methods, are also present in PD. To begin to assess this possibility, we quantified the complexity of 20 consecutive inspiratory (diaphragm EMG) bursts recorded during basal breathing in urethane-anesthetized spontaneously breathing adult female rats at 4-weeks after unilateral injection of 6-OHDA (n=18) or vehicle (VEH; n=14) directly into the substantia nigra (SN). For these analyses, we calculated approximate entropy (ApEn), which provides a statistical measure of regularity (orderliness) of a signal in the time domain, with values for the embedding dimension m and the tolerance r set to m=3 and r=0.44 SD. ApEn values were significantly higher in 6-OHDA-injected rats compared to VEH-injected rats (0.6169±0.0069 vs 0.5894±0.0087; P=0.017) albeit TI and Tpeak/TI were similar in both groups (TI: 305.8±9.5 vs 300.0±12.7 ms, P=0.713; Tpeak/TI: 51.0±1.3 vs 51.3±1.1%, P=0.904). Other significant differences in temporal features included higher breathing frequencies (93.4±2.4 vs 82.0±3.2 bpm; P=0.007), reduced TE (in ms: 334.7±12.7 vs 445.5±27.4; P=0.001), and decreased inspiratory duty cycle (in %: 47.2±1.1 vs 40.8±2.0; P=0.006) in 6-OHDA (compared to VEH)-injected rats. These observations suggest that respiratory dysfunction in PD is also accompanied by reorganization of the central inspiratory neural network that is associated with greater irregularity or less system order. Additional experiments are needed to identify the precise neural mechanisms underlying this higher system complexity. NIH NS101737; Thomas Hartman Center for Parkinson's Disease Research at Stony Brook University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Panax ginseng Ameliorates Pituitary-Ovarian Dysfunction Induced by Radiofrequency Electromagnetic Radiation from Cell Phones via Upregulation of the CREM Signaling Pathway.

Panax ginseng (PG) is a plant that contains ginsenosides, which are considered adaptogens that confer cellular protection. However, the impact of PG on pituitary-ovarian dysfunction and subsequent infertility is unknown. This study investigated the hypothesis that PG would attenuate pituitary-ovarian dysfunction associated with mobile phone's Radiofrequency Electromagnetic Radiation (RF-EMR) in experimental rat models and the possible involvement of a cAMP Response Element Modulator (CREM)-dependent pathway. Twenty adult female Wistar rats were divided randomly into four groups, each consisting of five rats. The control group was administered a vehicle (distilled water) orally, while the P. ginseng group received 200 mg/kg of P. ginseng extract orally. The RF-EMR group was exposed to 900MHz radiation, and the RF-EMR + PG group was exposed to the same radiation while also being treated with 200 mg/kg of P. ginseng orally. These treatments were administered daily for a period of 56 days. The RF-EMR group exhibited significant reductions in serum levels of LH, FSH, estradiol, and progesterone compared to the control group. Moreover, levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were significantly lower in the RF-EMR group compared to the control. Additionally, there was a notable decrease in the expression of the CREM gene, accompanied by disrupted pituitary/ovarian morphology in the RF-EMR group compared to the control. However, the administration of PG mitigated these changes. The findings of this study indicate that P. ginseng extract shields against pituitary-ovarian impairment linked to RF-EMR exposure from cell phones by boosting antioxidant capacity and promoting the CREM-dependent pathway.

Subacute Use of Aqueous Extract of Water Melon (Citrullus lanatus) Seeds Mitigates against Pyramidal Neuronal Toxicity of Lead Acetate in Adult Wistar Rats

Introduction: Lead exposure remains a significant public health burden across the globe, impacting millions of individuals and posing a major threat to nervous system development and function As a reported bio-toxic environmental and industrial pollutant, Lead (Pb) do accumulates in almost all body tissues to cause health complications with the cerebellar region of the central nervous system reported to be more susceptible to cellular distortions. As a flowering plant species of the Cucurbitaceae family, watermelon (Citrullus lanatus) is associated with numerous medicinal properties. Aim: This study aim to investigate the possible neuroprotective potential of aqueous extract of citrulus lanatus seed on lead acetates-induced neurotoxicity in the Cerebral cortex of adult Wistar rats. Place of Study: Department of Anatomy, Faculty of Basic Medical Sciences Olabisi Onabanjo University, Ogun State, Nigeria. Methods: Twenty (20) healthy adult female wistar rats weighing 150±50g were randomly assigned into 4 groups (n=5). The Control group received 2mls/kg of distilled water, Treatment group (T1) was administered 7.5 mg/kg of lead acetate, Treatment group (T2) was administered 200 mg/kg of aqueous extract of citrullus lanatus and Treatment group (T3) was administered 7.5 mg/kg of lead acetate and 200 mg/kg of aqueous extract of citrullus lanatus concomitantly orally for fourteen (14) days. H&amp;E and Cresyl violet histological stains and Biochemical assays for SOD, CAT activities and MDA concentration was determined. Data obtained from the study were analyzed using one-way ANOVA and subjected to Turkeys post hoc test from the multiple comparison. Results: Revealed no statistically significant differences (p&gt;0.05) in body weight and brain weight changes across groups relatives to the control group while SOD and Catalase activities were increased significantly in the Treatment groups compared to control group. Histological findings in control group and T2 showed normal histoarchitectural appearance of cerebral cortex Pyramidal neurons while the lead exposed group (T1) revealed features of neurodegenerative changes evident by nuclear shrinkage with pyknosis and karryorrhexis. while T3 revealed near normal presentations. Conclusion: In summary, Citrullus lanatus mitigates against pyramidal neuronal cells distortions following lead acetate induced toxicity in Wistar Rats and also further affirms its antioxidative potential.

EZH2-dependent epigenetic reprogramming in the central nucleus of amygdala regulates adult anxiety in both sexes after adolescent alcohol exposure

Alcohol use and anxiety disorders occur in both males and females, but despite sharing similar presentation and classical symptoms, the prevalence of alcohol use disorder (AUD) is lower in females. While anxiety is a symptom and comorbidity shared by both sexes, the common underlying mechanism that leads to AUD and the subsequent development of anxiety is still understudied. Using a rodent model of adolescent intermittent ethanol (AIE) exposure in both sexes, we investigated the epigenetic mechanism mediated by enhancer of zeste 2 (EZH2), a histone methyltransferase, in regulating both the expression of activity-regulated cytoskeleton-associated protein (Arc) and an anxiety-like phenotype in adulthood. Here, we report that EZH2 protein levels were significantly higher in PKC-δ positive GABAergic neurons in the central nucleus of amygdala (CeA) of adult male and female rats after AIE. Reducing protein and mRNA levels of EZH2 using siRNA infusion in the CeA prevented AIE-induced anxiety-like behavior, increased H3K27me3, decreased H3K27ac at the Arc synaptic activity response element (SARE) site, and restored deficits in Arc mRNA and protein expression in both male and female adult rats. Our data indicate that an EZH2-mediated epigenetic mechanism in the CeA plays an important role in regulating anxiety-like behavior and Arc expression after AIE in both male and female rats in adulthood. This study suggests that EZH2 may serve as a tractable drug target for the treatment of adult psychopathology after adolescent alcohol exposure.