Young Adult Male Rats Research Articles

The Effect of Exosomes from Adipose derived Mesenchymal Stem Cells in Photoaged Rat Skin versus Topically Applied Growth Factors. A Histological Study

Abstract Introduction Skin photoaging is characterized by coarse wrinkles, loss of elasticity and dryness. The worst scenario of ultraviolet (UV) ray exposure can reach up to skin malignant changes. The topical application of growth factors has proven to be effective in ameliorating the photoaging. Among the paracrine products of stem cells are exosomes which also play an important role. Aim of the Work To investigate the effect of exosomes derived from adipose mesenchymal stem cells on the histological structure of photoaged rat thin skin versus topically applied growth factors. Materials and Methods Forty-five young adult male albino rats aged between 6 - 8 weeks were used in this study. Animals were subjected to gentle shaving of the hair over the center of their backs and they were randomly classified into four groups. Control group (I), 20 rats were divided into four subgroups (five animals each). Subgroup Ia, animals were left without treatment, Subgroup Ib, animals were injected subcutaneously with 1 ml of Phosphate Buffer Saline (PBS) at the shaved areas. Subgroup Ic, shaved areas were topically treated with growth factors gel after micro-needling procedure (Three topical treatments were repeated each one performed every 10 days). Subgroup Id, rats were subcutaneously injected with one dose of purified exosome concentrate containing 300 µg of total protein. Group (II)– (photoaged untreated group), five rats, each was exposed to UVA + UVB irradiation for two weeks (five days per week) on the shaved areas using UV lamp. Group (III)- (photoaged exosome-treated group), five rats, each was exposed to UVA + UVB irradiation similar to group II. The animals were injected with one dose of purified exosome concentrate containing 300 µg of total protein subcutaneously at the shaved areas. Group (IV)- (Photoaged and topically treated with growth factors), five rats each was exposed to UVA + UVB irradiation similar to group II. Then, the animals were treated topically as in subgroup C. The back skin was dissected and processed to prepare sections for light microscopic examination with H&E, Masson’s trichrome, Orcein and PAS stains. Immunostaining for KI67and CD31 were done. Morphometric and statistical analysis were performed. Results Group II revealed significant decrease in the epidermal thickness, hair follicles were scanty and disorganized. Orcein sections showed short fragmented elastic fibers and irregular arrangement of collagen fibers with Masson’s trichrome stain. KI67 positive cells was higher than other groups and CD31 was the opposite. Groups III and IV showed marked decrease in the previously mentioned microscopic changes denoting amelioration of the recorded photoaged epidermal and dermal changes. Conclusion The current study concluded that both exosomes and topically applied Growth factors over three divided doses accompanied with micro-needling have resulted in a significant amelioration of the altered microscopic photoaging changes observed after exposure of the rat thin skin to the UV rays. Furthermore, the improvement was more obvious with the topically applied growth factors compared to one dose of exosomes concentrate. Further studies are recommended using repeated application of exosomes and also in combination with micro- needling to stabilize the best protocol for treatment.

Differential effects of exercise and hormone treatment on spinal cord injury-induced changes in micturition and morphology of external urethral sphincter motoneurons.

Spinal cord injury (SCI) results in lesions that destroy tissue and spinal tracts, leading to deficits in locomotor and autonomic function. We have previously shown that after SCI, surviving motoneurons innervating hindlimb muscles exhibit extensive dendritic atrophy, which can be attenuated by treadmill training or treatment with gonadal hormones post-injury. We have also shown that following SCI, both exercise and treatment with gonadal hormones improve urinary function. Animals exercised with forced running wheel training show improved urinary function as measured by bladder cystometry and sphincter electromyography, and treatment with gonadal hormones improves voiding patterns as measured by metabolic cage testing. The objective of the current study was to examine the potential protective effects of exercise or hormone treatment on the structure and function of motoneurons innervating the external urethral sphincter (EUS) after contusive SCI. Gonadally intact young adult male rats received either a sham or a thoracic contusion injury. Immediately after injury, one cohort of animals was implanted with subcutaneous Silastic capsules filled with estradiol (E) and dihydrotestosterone (D) or left blank; continuous hormone treatment occurred for 4 weeks post-injury. A separate cohort of SCI-animals received either 12 weeks of forced wheel running exercise or no exercise treatment starting two weeks after injury. At the end of treatment, urinary void volume was measured using metabolic cages and EUS motoneurons were labeled with cholera toxin-conjugated horseradish peroxidase, allowing for assessment of dendritic morphology in three dimensions. Locomotor performance was improved in exercised animals after SCI. Void volumes increased after SCI in all animals; void volume was unaffected by treatment with exercise, but was dramatically improved by treatment with E + D. Similar to what we have previously reported for hindlimb motoneurons after SCI, dendritic length of EUS motoneurons was significantly decreased after SCI compared to sham animals. Exercise did not reverse injury-induced atrophy, however E + D treatment significantly protected dendritic length. These results suggest that some aspects of urinary dysfunction after SCI can be improved through treatment with gonadal hormones, potentially through their effects on EUS motoneurons. Moreover, a more comprehensive treatment regime that addresses multiple SCI-induced sequelae, i.e., locomotor and voiding deficits, would include both hormones and exercise.

Abstract P351: Obesity in Early Life Leads to Endothelial and Erectile Dysfunction in Young Adult Rats.

Background: Erectile dysfunction (ED) is largely associated with obesity, however, the consequences of early life obesity for ED in young adulthood are unknown. We hypothesize that obesity induced by preweaning overfeeding impairs vascular and erectile function and affects blood pressure in young adult male rats (5-month-old). Methods: At postnatal day (PND) 1, Wistar rats were divided into a normal litter (NL, 5 female + 5 male pups/dam) or small litter (SL, 2 male + 1 female pup/dam) during lactation. After weaning, SL pups had increased body weight. Next, rats from both groups returned to normal size colonies (4-5 rats per cage) and were fed standard chow. At PND160, we evaluated body weight and fat pad deposition, mean arterial pressure (MAP) by tail-cuff, and pudendal artery (PA) and corpus cavernosum (CC) reactivity. Concentration-response curves to phenylephrine (PE) or acetylcholine (ACh) were performed in both preparations. In the CC, contraction and relaxation to electrical field stimulation (EFS) were obtained. Concentration-response curves were analyzed using non-linear regression analysis. RNA sequencing (RNAseq) analyses were performed in both PA and CC. Data were analyzed by Student’s t-test and presented as mean ± S.E.M. Statistical significance was set at p<0.05. Results: At PND160 no differences in body weight were observed in SL (594±14g) compared to NL (559±13g), however, there was an increase in fat deposition in SL (retroperitoneal fat: NL 7.47±0.69g vs SL 11.25±1.23g; perigonadal fat: NL 10.05±0.55g vs SL 13.24±1.16g). MAP was higher in SL (120.5±1.20 mmHg vs 114.9±0.58 NL). In the PA, ACh-induced relaxation was reduced in SL (Emax: 28±6%) vs NL (Emax: 68±5.5%), with no changes in the contraction to PE. In the CC, EFS-induced relaxation was significantly decreased in SL rats compared to NL rats (16 Hz: NL 3.06 ± 0.28% vs SL 2.39 ± 0.53%). RNAseq revealed that, in PA from SL rats, 289 and 224 genes were down and upregulated, respectively, while in the CC from SL rats, 115 genes were downregulated, and 110 genes were upregulated. Among them, hcn2 gene (which encodes HCN2, the hyperpolarization-activated cyclic nucleotide-gated potassium and sodium channel 2) was strongly downregulated in both PA and CC, and this may affect mechanotransduction. Conclusion: Our data shows that early-life obesity causes long-lasting vascular and cavernous damage that might be associated with endothelial and erectile dysfunction in young adulthood.

Combination of low doses of mirtazapine plus venlafaxine produces antidepressant-like effects in rats, without affecting male or female sexual behavior.

Pharmacological treatments for depression are not always effective and produce unwanted side effects. Male and female sexual dysfunction is one of these side effects, which can lead to treatment withdrawal. Combination of two antidepressants with different mechanisms of action, like mirtazapine (MTZ) and venlafaxine (VLF) have been shown to be effective for treatment-resistant depression in humans. Combination of low doses of these drugs may still exert antidepressant-like effects without altering sexual behavior. To investigate the potential antidepressant-like effect of the chronic administration of low doses of MTZ plus VLF combined, as well as its impact on male and female sexual behavior in rats. The antidepressant-like effect of a 14-day treatment with combinations of MTZ plus VLF (0/0, 2.5/3.75 or 5/7.5mg/kg) was assessed in young adult male and female rats in the forced swim test (FST). The 5/7.5mg/kg MTZ/VLF combination was also tested in the chronic mild stress (CMS) test, in both males and females treated for 21days. The sexual effects of this last treatment were assessed in sexually experienced males and in gonadally-intact females during proestrus. The 5/7.5mg/kg MTZ/VLF combination produced an antidepressant-like effect in the FST and reversed the CMS-induced anhedonia in both male and female rats. This combination did not alter male sexual behavior, female proceptive and receptive behaviors or the regularity of the estrous cycle. The combination of low doses of MTZ and VLF might be a promising therapeutic alternative to treat depression without affecting the sexual response.

Velocity of cerebrospinal fluid in the aqueduct measured by phase-contrast MRI in rat.

Cerebrospinal fluid (CSF) circulation plays a key role in cerebral waste clearance via the glymphatic system. Although CSF flow velocity is an essential component of CSF dynamics, it has not been sufficiently characterized, and particularly, in studies of the glymphatic system in rat. To investigate the relationship between the flow velocity of CSF in the brain aqueduct and the glymphatic waste clearance rate, using phase-contrast MRI we performed the first measurements of CSF velocity in rats. Phase-contrast MRI was performed using a 7T system to map mean velocity of CSF flow in the aqueduct in rat brain. The effects of age (3months old versus 18 months old), gender, strain (Wistar, RNU, Dark Agouti), anesthetic agents (isoflurane versus dexmedetomidine), and neurodegenerative disorder (Alzheimer' disease in Fischer TgF344-AD rats, males and females) on CSF velocity were investigated in eight independent groups of rats (12 rats per group). Our results demonstrated that quantitative velocities of CSF flow in the aqueduct averaged 5.16 ± 0.86 mm/s in healthy young adult male Wistar rats. CSF flow velocity in the aqueduct was not altered by rat gender, strain, and the employed anesthetic agents in all rats, also age in the female rats. However, aged (18 months) Wistar male rats exhibited significantly reduced the CSF flow velocity in the aqueduct (4.31 ± 1.08 mm/s). In addition, Alzheimer's disease further reduced the CSF flow velocity in the aqueduct of male and female rats.

Morin Prevents Non-Alcoholic Hepatic Steatosis in Obese Rats by Targeting the Peroxisome Proliferator-Activated Receptor Alpha (PPARα).

Obesity has become a widespread issue globally. Morin, a flavonoid with traditional use in managing hyperglycemia and hyperlipidemia, has demonstrated antioxidant and anti-inflammatory properties in experimental studies. This research aims to explore the anti-obesity potential of morin in rats subjected to a high-fat diet (HFD) and investigate whether its effects are mediated through PPARα regulation. Young adult male Wistar albino rats were divided into four groups (n = 8/group): normal, morin (50 mg/kg/BWT, oral), HFD, and HFD + morin (50 mg/kg/BWT, oral). Treatments were administered daily for 17 consecutive weeks. Morin mitigated the elevation in glucose levels and decreased fasting glucose and insulin levels, along with the HOMA-IR index, in HFD-fed rats. Furthermore, morin reduced calorie intake, final body weights, and the masses of subcutaneous, epididymal, peritoneal, and mesenteric fat in these rats. It also attenuated the rise in systolic blood pressure in HFD-fed rats and decreased serum levels of triglycerides, cholesterol, free fatty acids, LDL-c, and leptin, while increasing levels of HDL-c and adiponectin in both normal and HFD-fed rats. Moreover, morin restored normal liver structure and reduced fat vacuole accumulation in HFD-fed rats. Notably, it upregulated mRNA levels of PPARα in the livers and white adipose tissue of both normal and HFD-fed rats. These findings suggest the potential use of morin to enhance fatty acid oxidation in white adipose tissue and mitigate obesity, warranting further clinical investigation into its therapeutic applications.

Alterations to the copulatory sequence in young adult male Sprague–Dawley rats administered a ketogenic diet

Ketogenic diets (KDs) have shown therapeutic potential for a range of neuropsychiatric disorders; however, there is insufficient data regarding the behavioral impacts of KDs in healthy populations. Here, we examined the impact of a KD on sexual behavior in young adult male Sprague-Dawley rats maintained on either a KD or standard chow diet (SD). We found that KD males exhibited higher mount rates, higher intromission rates (third and fourth tests only), and lower ejaculation likelihood (second test only) compared to SD males. Consequently, it may be that experience-dependent changes in the processing of sexual stimuli are not occurring as efficiently in KD males, thereby yielding the observed copulatory sequence alterations.

Polyethylene glycol fusion repair of severed rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord.

JOURNAL/nrgr/04.03/01300535-202507000-00030/figure1/v/2024-09-09T124005Z/r/image-tiff Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions; behavioral recovery is typically poor. We used a plasmalemmal fusogen, polyethylene glycol (PEG), to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves. We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration, and PEG-fused animals exhibit rapid (within 2-6 weeks) and extensive locomotor recovery. Furthermore, our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific, i.e., spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles. In this study, we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve. Young adult male and female rats (Sprague-Dawley) received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without (Negative Control) the application of PEG. Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site. The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively. At 2-42 days postoperatively, we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase. PEG-fusion repair reestablished axonal continuity. Compared to unoperated animals, labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn, as well as inappropriate mediolateral and rostrocaudal areas. Unexpectedly, despite having intact peripheral nerves, similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair. This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair, supporting the use of this novel repair methodology over currently available treatments.

Ocimum GratissimumLinn. Leaf Extract and Fractions Pre-Treatments are not Associated With Deleterious Electrocardiogram Changes inTrastuzumab-Intoxicated Wistar Rats

Trastuzumab (TZM) treatment is known to be associated with arrhythmogenic potentialwhich primarily is the basis for its cardiotoxicity. The purpose of this study was to investigate the acute influence of oral pretreatments with 100 mg/kg/day of Ocimun gratissimumethanolic leaf extract (OG) and its fractions (petroleum ether,PEOG; ethyl acetate,EAOG; and ethanolic extract, EOG) as well as valsartan-lisinopril fixed dose combination (VAL-LSP) on electrocardiogram (ECG) of Wistar rats intaperitoneally treated with 2.25 mg/kg/day TZMfor 7 days. Young adult male Wistar rats were randomly allotted into 12groups of 6 rats per group. Therats were subjected to electrocardiograms (ECG) measurement using non-invasive procedures on days 1 and 7 of the experiment. Results showed that oral pretreatment with OGand its fractions (except EOG) as well as VAL-LSP fixed dose combination did not cause any remarkable changes in the ECG patterns of TZM-treated rats indicating that their relative oral safety in TZMchemotherapy. On the other hand, EOGpretreatment caused significant shortening of the OT/QTc interval in the TZM-treated rats highlighting the arrhthymogenic potential of this fraction. Overall, the study highlighted the arrhythmogenic potential of EOG in TZM chemotherapy while OG and its other solvent fractions as well as VAL-LSP could be considered relatively safe for use as adjuvants in TZM chemotherapy

Metformin treatment prevents experimental metabolic syndrome-induced femoral bone marrow adiposity in rats.

Motivation for the study. Most research supports a negative association between metabolic syndrome and bone health, although there is an overall lack of consensus. Therefore, there is a need for research in this area to develop a better understanding. Main findings. Metabolic syndrome induced by a fructose-rich diet increases the adipogenic predisposition of bone marrow progenitor cells and femoral medullary adiposity in rats. Furthermore, this can be partially prevented by co-treatment with metformin. Implications. Experimental metabolic syndrome has negative effects on bone tissue and can be prevented by oral treatment with metformin as a normoglycemic drug. To determine the effect of metformin (MET) treatment on adipogenic predisposition of bone marrow progenitor cells (BMPC), bone marrow adiposity and bone biomechanical properties. 20 young adult male Wistar rats were sorted into four groups. Each of the groups received the following in drinking water: 100% water (C); 20% fructose (F); metformin 100 mg/kg wt/day (M); or fructose plus metformin (FM). After five weeks the animals were sacrificed. Both humeri were dissected to obtain BMPC, and both femurs were dissected to evaluate medullary adiposity (histomorphometry) and biomechanical properties (3-point bending). BMPC were cultured in vitro in adipogenic medium to evaluate RUNX2, PPAR-γ and RAGE expression by RT-PCR, lipase activity and triglyceride accumulation. The fructose-rich diet (group F) caused an increase in both triglycerides in vitro, and medullary adiposity in vivo; being partially or totally prevented by co-treatment with metformin (group FM). No differences were found in femoral biomechanical tests in vivo, nor in lipase activity and RUNX2/PPAR-γ ratio in vitro. DRF increased RAGE expression in BMPC, being prevented by co-treatment with MET. Metabolic syndrome induced by a fructose-rich diet increases femoral medullary adiposity and, in part, the adipogenic predisposition of BMPC. In turn, this can be totally or partially prevented by oral co-treatment with MET.

Sex hormone supplementation improves breathing and restores respiratory neuroplasticity following C2 hemisection in rats.

In addition to loss of sensory and motor function below the level of the lesion, traumatic spinal cord injury (SCI) may reduce circulating steroid hormones that are necessary for maintaining normal physiological function for extended time periods. For men, who comprise nearly 80% of new SCI cases each year, testosterone is the most abundant circulating sex steroid. SCI often results in significantly reduced testosterone production and may result in chronic low testosterone levels. Testosterone plays a role in respiratory function and the expression of respiratory neuroplasticity. When testosterone levels are low, young adult male rats are unable to express phrenic long-term facilitation (pLTF), an inducible form of respiratory neuroplasticity invoked by acute, intermittent hypoxia (AIH). However, testosterone replacement can restore this respiratory neuroplasticity. Complicating the interpretation of this finding is that testosterone may exert its influence in three possible ways: 1) directly through androgen receptor (AR) activation, 2) through conversion to dihydrotestosterone (DHT) by way of the enzyme 5α-reductase, or 3) through conversion to 17β-estradiol (E2) by way of the enzyme aromatase. DHT signals via AR activation similar to testosterone, but with higher affinity, while E2 activates local estrogen receptors. Evidence to date supports the idea that exogenous testosterone supplementation exerts its influence through estrogen receptor signaling under conditions of low circulating testosterone. Here we explored both recovery of breathing function (measured with whole body barometric plethysmography) and the expression of AIH-induced pLTF in male rats following C2-hemisection SCI. One week post injury, rats were supplemented with either E2 or DHT for 7days. We hypothesized that E2 would enhance ventilation and reveal pLTF following AIH in SCI rats. To our surprise, though E2 did beneficially impact overall breathing recovery following C2-hemisection, both E2 supplementation and DHT restored the expression of AIH-induced pLTF 2weeks post-SCI.

The effect of magnesium sulfate on memory and anxiety-like behavior in a rat model: an investigation of its neuronal molecular mechanisms

ABSTRACT Background Anxiety is an adaptive response to potentially threatening conditions. Excessive and uncontrolled anxiety responses become nonadaptive and cause anxiety disorders. To better understand the anxiety-modulating effects of Mg sulfate, behavioral test batteries in the assessment of anxiety and learning and memory functions were performed simultaneously over a time period. This study also examines the effects of Mg sulfate compared to diazepam, an anxiolytic drug with amnestic effects on anxiety-like behavior, as well as possible oxidative-nitrosative stress and hippocampal changes in male rats exposed to predator odor. Methods Young adult Sprague-Dawley male rats were used. The rats were assessed using a comprehensive neurobehavioral test battery consisting of novel object recognition, open field, and successive alleys tasks. Anxiety was induced by cat odor, and diazepam and Mg were used as study drugs. Of the frontal cortex and hippocampus, the state of total oxidant and antioxidant and NO levels and histological examination of hippocampal CA1, CA2, CA3, and DG regions were performed. Results Diazepam- and Mg-treated rats showed an improvement in anxiety-related behavior to predator odors. Furthermore, Mg treatment alleviated some of the increasing oxidative stress in the frontal cortex and hippocampus of rats, while diazepam treatment in particular enhanced hippocampal oxidant and antioxidant activity. In addition, brain NO increase induced by animal odor exposure or diazepam treatment was ameliorated by Mg administration. Conclusions Overall, our work suggests that Mg had a partial anxiolytic effect on anxiety-like behaviors, although not as much as diazepam, and this effect varied depending on the dose. Mg treatment might counteract increased oxidative stress and elevated NO levels in the brain.

Motor function is not impaired in all components of the oral phase of feeding in a rat rotenone model of Parkinson’s disease

Parkinson’s disease results in pathological swallowing, or dysphagia, in up to 90% of cases. Severity and extent of functional impairment of feeding is highly variable in this disease. Feeding is a multi step neuromuscular process of tightly coordinated orofacial behaviors -transport, food reduction, pharyngeal swallowing- involving multiple musculoskeletal systems — tongue, jaw muscles, hyolaryngeal muscles — innervated by multiple cranial and cervical spinal nerves. The type of food being ingested further affects this sequence. The pesticide rotenone, a type II mitochondrial inhibitor, has been epidemiologically linked to Parkinson’s disease. The goal of this project is to identify how parkinsonian neurodegeneration affects this sequence in an animal model. We hypothesize that not all elements of the sequence will be equally affected. Twelve young adult male Lewis rats received daily intraperitoneal injections of either 2.75 mg/kg of rotenone or vehicle control for 8 days. The rats were trained to eat breakfast cereal and drink water mixed with barium in front of a high speed (200 fps) videofluoroscope. From the high speed video recording duration of intraoral transport and chewing of solid food as well as lick duration for liquid drinking were measured for multiple swallows per individual on day 0 (before injection), day 1, day 4, and day 7. On day 8 animals were perfused and brains harvested, sliced, stained with immunofluorescent markers for striatal tyrosine hydroxylase to confirm effectiveness of the model. Mixed model ANOVA was used to test the hypothesis that duration of the phases varied over the course of treatment. Duration of intra oral transport changed in neither control nor rotenone treated animals (p=0.1136), but duration of chewing increased in rotenone treated rats only by day 4 (p<0.001). Duration of licks increased in liquid drinking rats from day 0. Different components of the oral feeding process vary in degree and timing of impairment in the rat rotenone model of Parkinson’s disease, with coordinated rhythmic tongue and jaw movements (licking and chewing) being most sensitive. The neurological basis for this differential sensitivity remains unclear. Internal Rowan funds to Dr. Gould supported this work. 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.

Attenuation of ventriculomegaly and iron overload after intraventricular hemorrhage by membrane attack complex inhibition.

The pathophysiology of posthemorrhagic hydrocephalus (PHH) is not well understood, but recent data suggest blood components play a significant role. This study aimed to understand the timing of membrane attack complex (MAC) activation after intraventricular hemorrhage (IVH) and the effect of MAC inhibition on PHH development. This study was composed of four parts. First, 24 young adult male rats underwent stereotactic intraventricular injection of autologous blood or saline and MRI on day 1, 3, or 7 after hemorrhage. Second, 18 rats underwent intraventricular injection of saline, autologous blood with aurin tricarboxylic acid (ATA) in vehicle, or autologous blood with vehicle and underwent serial MRI studies on days 1 and 3 after hemorrhage. Third, 12 rats underwent intraventricular injections as above and MRI 2 hours after hemorrhage. Finally, 24 rats underwent the intraventricular injections as above, as well as serial MRI studies on days 1, 7, 14, and 28 after hemorrhage. The MR images were used to calculate ventricular volume and iron deposition. Open field testing was performed to assess functional outcomes. Outcomes on day 28 were reported as a ratio to the animal's baseline values and normalized via log-transformation. Statistical analysis included the Shapiro-Wilk tests for normality and t-tests and 1-way analysis of variance for 2 and 3 groups of continuous variables, respectively. MAC was found within the hematoma 1 day after hemorrhage and persisted until day 7. Administration of ATA resulted in similar intraventricular hematoma volumes compared to vehicle 2 hours after hemorrhage. At 1 and 3 days after hemorrhage, ATA administration resulted in significantly smaller ventricular volumes and less hemolysis within the hematoma than in the vehicle animals. Administration of ATA also resulted in significantly smaller ventriculomegaly and less iron deposition in the periventricular area than in the vehicle rats 28 days after hemorrhage. Functionally, ATA rats were significantly faster, traveled longer distances, and spent less time resting than vehicle rats at 28 days. MAC was activated early and persisted within the hematoma until day 7 after IVH. MAC inhibition attenuated hemolysis in the clot and ventriculomegaly acutely after IVH. One month after hemorrhage, MAC inhibition attenuated ventriculomegaly and iron accumulation and improved functional outcomes.

Chronic unpredictable mild stress increases serum aldosterone without affecting corticosterone levels and induces hepatic steatosis and renal injury in young adult male rats.

Stress is often associated with anxiety and depressive symptoms in adolescents. Stress is associated with components of metabolic syndrome and inflammation. The present study hypothesizes that aldosterone, more than corticosterone, promotes chronic stress-hepatic steatosis and fibrosis, as well as renal inflammation and fibrosis in young adult rats. Thirty-two young adult male Wistar rats of 51 days old were divided into four groups (n = 8 per group): Control (C), chronic unpredictable mild stress (CUMS), control plus vehicle (C plus veh), CUMS plus eplerenone, a selective aldosterone blocker (CUMS plus EP). On postnatal day 51, eplerenone was administered orally through a gastric tube two hours before the start of the stress test. The CUMS paradigm was administered once daily at different times, with no repetition of the stressor sequence for four weeks. Renal inflammation and fibrosis were measured, as well as liver glycogen, triacylglycerol, and fibrosis levels. The serum concentrations of corticosterone, aldosterone, sodium, and creatinine were measured in urine and serum. The CUMS group showed a high level of serum aldosterone without affecting the level of corticosterone, increased urinary sodium, tubular atrophy, glomerular sclerosis, the presence of inflammation, and fibrosis, without affecting creatinine, increased glycogen content, triacylglycerol, and moderate fibrosis in the liver, and treatment with eplerenone prevented the inflammation, fibrosis, glycogen, and triacylglycerol. Our results show that chronic stress-induced aldosterone promotes hepatic steatosis and renal injury more than corticosterone. The prevention by eplerenone supports our hypothesis.

Neurobehavioral Abnormalities in Offspring of Young Adult Male Rats With a History of Traumatic Brain Injury.

Children of parents with traumatic brain injury (TBI) are more likely to develop psychiatric disorders. This association is usually attributed to TBI-induced changes in parents' personality and families' social environment. We tested the hypothesis that offspring of young adult male rats with TBI develop neurodevelopmental abnormalities in the absence of direct social contact with sires. Male Sprague-Dawley rats (F0 generation) in the TBI group underwent moderate TBI via a midline fluid percussion injury that involved craniectomy under sevoflurane (SEVO) anesthesia for 40 min on post-natal Day 60 (P60), while F0 rats in the control group were placed in a new cage, one per cage, for the equivalent time duration. A subset of F0 rats was sacrificed on P66 to assess acute changes in hypothalamic-pituitary-adrenal (HPA) axis and inflammation markers. The remaining F0 males were mated with naive females on P90 to generate offspring (F1 generation). The F0 males and F1 males and females were sequentially evaluated in the elevated plus maze, for pre-pulse inhibition of acoustic startle, in the Morris water maze, and for resting and stress levels of serum corticosterone starting on ∼P105 (F0) and ∼P60 (F1), followed by tissue collection for further analyses. Acutely, the F0 TBI males had messenger RNA (mRNA) transcripts altered to support an increased hypothalamic and hippocampal Na+-K+-Cl- (Slc12a2) Cl- importer / K+-2Cl- (Slc12a5) Cl- exporter ratio and decreased hippocampal glucocorticoid receptors (Nr3c1), as well as increased serum levels of corticosterone, interleukin-1β (IL-1β), and biomarkers of activated hippocampal microglia and astrocytes. Long-term, F0 TBI rats exhibited increased corticosterone concentrations at rest and under stress, anxiety-like behavior, impaired sensory-motor gating, and impaired spatial memory. These abnormalities were underpinned by reduced mRNA levels of hypothalamic and hippocampal mineralocorticoid receptors (Nr3c2), hippocampal Nr3c1, and hypothalamic brain-derived neurotrophic factor (Bdnf), as well as elevated serum levels of IL-1β, and biomarkers of activated hippocampal microglia and astrocytes. F1 male offspring of TBI sires exhibited abnormalities in all behavioral tests, while their F1 female counterparts had abnormal pre-pulse inhibition responses only. F1 male offspring of TBI sires also had reduced mRNA levels of hippocampal Nr3c1 and Nr3c2, as well as hypothalamic and hippocampal Bdnf, whereas increases in inflammatory markers were more profound in F1 females. These findings suggest that offspring of sires with a history of a moderate TBI that involved craniectomy under SEVO anesthesia for 40 min, develop sex-dependent neurobehavioral abnormalities in the absence of direct social interaction between the sire and the offspring.

Calcium restriction for 28 days markedly and negatively influences bone mineral density of the femur and lumbar vertebrae regardless of the high-fat diet ingestion in young adult male rats

Calcium (Ca) is necessary for bone calcification, and Ca deficiency leads to decreased bone mineral density (BMD). Epidemiological studies have reported a correlation between Ca intake and BMD. Although the influences of Ca deficiency on BMD have been reported, the effects of Ca restriction on bone during high-fat diet ingestion remain unclear. Therefore, we hypothesized that high-fat diet ingestion would potentiate the negative effects of Ca restriction on bone. Sprague-Dawley strain male rats (aged 11 weeks) were divided into 4 groups: basic control diet (Cont.) (11% lipid energy rate, 0.5% calcium), basic control diet with Ca restriction (CaR) (11% lipid energy rate, 0.02% calcium), high-fat diet (HF) (40% lipid energy rate, 0.5% calcium), and high-fat diet with Ca restriction (HFCaR) (40% lipid energy rate, 0.02% calcium). At 28 days after starting the experimental diets, body weights were higher in the high-fat diet groups (HF and HFCaR) than in the standard-fat diet groups (Cont. and CaR) on 2-way analysis of variance. The apparent Ca absorption rate in the Ca-restricted groups (CaR and HFCaR) was higher than in the Ca-sufficient groups (Cont. and HF). BMD and bone strength parameters of the femur and lumbar vertebrae in the Ca-restricted groups were markedly lower than in the Ca-sufficient groups, whereas there were no significant differences between the standard-fat diet and HF diet groups. These results suggest that 28 days of Ca restriction increases the risk of bone fracture and osteoporosis.

Age differences in the impact of dietary salt on metabolism, blood pressure and cognitive function in male rats.

The influence of salt consumption on physiological processes, especially blood pressure (BP), metabolism, and cognition, remains a topical concern. While guidelines endorse reduced salt diets, there are gaps in understanding the age-specific implications and challenges in adherence. The present study delved into the differential effects of salt intake on young adult and aged male rats over a 12-week period, using control, low-, and high-salt diets. Key metrics, such as BP, cognition, and general parameters, were monitored. Our findings revealed significant age-dependent effects of salt intake on survival rates, body weight, blood sodium, blood glucose, blood lipids, BP, heart rates, and cognition. Notably, young adult rats did not show significant sodium level changes on a high-salt diet, whereas aged rats experienced increased sodium levels even on a normal salt diet. Blood glucose levels decreased significantly in aged rats on a high-salt diet but remained stable in young adults. Aged rats had the highest survival rates on low-salt diets. Low-salt diets led to reduced BP in both age groups, more significantly in young adults. Young adult rats displayed increased BP variability on both high- and low-salt diets, while a decrease in BP variability was exclusive to aged rats on a low-salt diet. There were significant differences across age groups in short-term memory, but not in long-term memory. The study provides a nuanced understanding of the age-dependent physiological effects of salt intake, suggesting the necessity of age-specific guidelines for public health.

Daily fluctuations in blood glucose with normal aging are inversely related to hippocampal synaptic mitochondrial proteins

Defective brain glucose utilization is a hallmark of Alzheimer’s disease (AD) while Type II diabetes and elevated blood glucose escalate the risk for AD in later life. Isolating contributions of normal aging from coincident metabolic or brain diseases could lead to refined approaches to manage specific health risks and optimize treatments targeted to susceptible older individuals. We evaluated metabolic, neuroendocrine, and neurobiological differences between young adult (6 months) and aged (24 months) male rats. Compared to young adults, blood glucose was significantly greater in aged rats at the start of the dark phase of the day but not during the light phase. When challenged with physical restraint, a potent stressor, aged rats effected no change in blood glucose whereas blood glucose increased in young adults. Tissues were evaluated for markers of oxidative phosphorylation (OXPHOS), neuronal glucose transport, and synapses. Outright differences in protein levels between age groups were not evident, but circadian blood glucose was inversely related to OXPHOS proteins in hippocampal synaptosomes, independent of age. The neuronal glucose transporter, GLUT3, was positively associated with circadian blood glucose in young adults whereas aged rats tended to show the opposite trend. Our data demonstrate aging increases daily fluctuations in blood glucose and, at the level of individual differences, negatively associates with proteins related to synaptic OXPHOS. Our findings imply that glucose dyshomeostasis may exacerbate metabolic aspects of synaptic dysfunction that contribute to risk for age-related brain disorders.

An Evaluation of the Effectiveness of Melatonin and n-Acetylcysteine in Cerebral Ischemia-Reperfusion Injury in Adult Rats.

Background and Objectives: The purpose of this study was to apply histopathological and immunohistochemical methods to compare the protective efficacy of melatonin and N-acetylcysteine (NAC) application in rats with experimental brain ischemia/reperfusion (I/R) injury induced through occlusion of the middle cerebral artery (MCA), and to evaluate the protective effect of their combined use. Materials and Methods: Forty-one young adult male Wistar albino rats were divided into five groups-control (n = 8), I/R group (n = 8), melatonin (n = 8), NAC (n = 8), and melatonin + NAC (n = 9). Results: All scores differed between the groups, apart from vascular congestion (p < 0.05). At two-way comparisons, all histological scores were significantly higher in the I/R group than in the control group (p < 0.05). No change occurred in the vascular congestion scores with the administration of melatonin, although decreases were determined in all other scores. These decreases were statistically significant for cellular eosinophilic pyknotic degeneration, vacuolization, and edema (p < 0.05). All histopathological scores in the group administered NAC together with melatonin were significantly lower than in the I/R group (p < 0.05). Conclusions: The combined use of NAC and melatonin, the neuroprotective efficacy of which on histopathological parameters is shown in this study, now needs to be supported by further research.