Blood Corticosterone Research Articles

Chronic psychosocial stress affects insulin-like growth factor 1 and its receptors in mouse ovaries.

Context Chronic psychosocial stress negatively affects folliculogenesis and oogenesis. Intraovarian mechanisms mediating these effects are poorly understood. Aims This work aimed to find out how chronic psychosocial stress affects ovarian IGF1 and its receptor (IGF1R), as well as Igf1 and Igf1r gene expression in cumulus-oocyte complexes (COCs). It also aimed to address possible protective effects of gonadotropin stimulation on IGF1 ovarian signalling. Methods Female CD1 mice experienced chronic psychosocial stress of 11-day isolation followed by overcrowding for 10days. To verify the model, blood corticosterone levels and the quality of oocytes were evaluated in stressed females. The levels of IGF1/IGF1R, blood IGF1 concentration, and expression of Igf1 /Igf1r in the ovaries were compared in stressed and unstressed females. Key results Psychosocial stress caused an elevation of corticosterone level, which was alleviated by gonadotropin treatment. The stressed mice showed a decreased IGF1 level in the ovaries and a decreased expression of Igf1 and Igf1r in COCs. In the unstressed females, gonadotropin injection decreased the expression of Igf1 and Igf1r ; in the stressed females, the same treatment increased Igf1r expression. Neither stress nor ovarian stimulation with gonadotropins affected the serum IGF1 level. Conclusions Psychosocial stress suppresses IGF1 signalling in the ovaries. Gonadotropin treatment modulates these effects differently in stressed and unstressed animals. Implications The results may have translational value for human reproduction. Ovarian IGF1 can be considered a candidate for further improvement of IVF results in women under conditions of chronic stress.

7561 Maternal Sucrose Consumption During Gestation Alone Does Not Affect Glucocorticoids and Aldosterone in the Fetal Brain and Blood of Rats

Abstract Disclosure: M.M. Jung: None. D.R. Seib: None. M. Idrissi: None. H.W. Chen: None. K.K. Soma: None. Sucrose (table sugar) is a common added sugar in foods and beverages. Sucrose intake is high worldwide, yet little is known about how sucrose affects the brain and hormones. We designed an isocaloric, macro/micro-nutrient matched control diet (1% kcal sucrose) and high-sucrose diet (26% kcal sucrose) paradigm where the two diets only differ in kcal from sucrose. In this paradigm, maternal high-sucrose diet intake alters glucocorticoids (GCs) which are steroid hormones that regulate numerous physiological processes including the stress response. 16 wk of maternal sucrose intake (10 wk before mating, 3 wk during gestation, and 3 wk during lactation) increases blood and brain corticosterone levels in adult female offspring. Moreover, 13 wk of maternal sucrose intake (10 wk before mating and 3 wk during gestation) increases 11-deoxycorticosterone (DOC, corticosterone precursor) and 11-dehydrocorticosterone (DHC, corticosterone metabolite) in maternal serum, and increases aldosterone in fetal blood and brain at embryonic day 19.5 (E19.5). These results suggest that long-term maternal sucrose intake is a stressor that alters GC and aldosterone signalling. It is unclear whether a maternal high-sucrose diet only during gestation alters fetal steroid levels, or whether long-term sucrose consumption before mating is necessary. Here, we investigate the effects of maternal sucrose intake during gestation only on GCs and aldosterone in the fetal blood and brain. We hypothesize that maternal sucrose intake only during gestation will alter GC and aldosterone signaling in the fetus. We predict that maternal sucrose consumption during gestation alone will increase GC and aldosterone levels in the fetal blood and brain. Female Long-Evans rats were fed either a high-sucrose diet or a control diet starting E0.5 (day of mating confirmation) (n=15/diet). On E19.5, we collected fetal brain and blood and microdissected the regions of the fetal brain that are sensitive to GCs and aldosterone: nucleus accumbens, amygdala, hypothalamus, ventral hippocampus, and ventral tegmental area. We measured a panel of 15 steroids including GCs and aldosterone in the fetal brain (0.8-1.6 mg/region) and blood (5 µL) using liquid chromatography-tandem mass spectrometry, the gold standard for steroid quantification. Maternal high-sucrose diet intake during gestation alone did not alter maternal food intake, maternal body mass, or litter size, but increased the percentage of male offspring per litter. Maternal sucrose intake did not alter DOC, corticosterone, or DHC levels in the fetal blood and brain regions. Aldosterone was not detected in the fetal blood and brain. These results suggest that maternal sucrose intake during gestation alone does not alter GC and aldosterone levels in the developing fetus and that a longer duration of maternal sucrose intake is needed to alter offspring endocrine physiology. Presentation: 6/1/2024

Oral Supplementation of L-Carnosine Attenuates Acute-Stress-Induced Corticosterone Release and Mitigates Anxiety in CD157 Knockout Mice.

Corticosterone, an end product of the hypothalamic-pituitary-adrenal (HPA) axis, is a crucial stress hormone. A dysregulated HPA axis and corticosterone release play pivotal roles in the onset and persistence of symptoms of stress-related psychiatric disorders, such as anxiety. The intake of nutrients, probiotics, and prebiotic supplements decreases blood corticosterone levels. The dipeptide L-carnosine is composed of beta-alanine and L-histidine and is commercially available as a nutritional supplement for recovery from fatigue. L-carnosine is involved in stress-induced corticosterone responses and anxiety behaviors in rodents. Here, we assessed the effect of L-carnosine in CD157 knockout (KO) mice, a murine model of autism spectrum disorder (ASD). The uptake of L-carnosine suppressed the increase in plasma corticosterone levels in response to acute stress and attenuated anxiety-like behaviors in CD157 KO mice. These results suggest that L-carnosine supplementation may relieve anxiety by suppressing excessive stress responses in individuals with ASD.

Mechanisms of adaptation of the hypothalamic-pituitary-adrenal axis in male mice under chronic social defeat stress

The hypothalamic-pituitary-adrenal axis (HPA) plays an important role in the mechanisms of adaptation to chronic stress. A model of chronic social defeat stress (CSDS), based on the experience of defeat in daily agonistic interactions, causes the development of a depressive-like state in mice, which is often accompanied by an increase in blood corticosterone levels. In this work, we assessed what changes occur in the central (hypothalamus) and peripheral (adrenal glands) parts of the HPA axis under the influence of chronic social stress, which can affect the regulation of corticosterone synthesis and its level in the blood. The experience of chronic social stress causes an increase in the relative weight of the adrenal glands, an increase in the expression level of Crh gene in the hypothalamus and the expression of the genes for the corticosterone synthesis enzymes Star, Cyp11a1, Cyp11b1 in the adrenal glands. At the same time, in the hypothalamus the expression of Fkbp5 and Nr3c1 decreases and the expression of Crhbp increases, and in the adrenal glands the expression of the Mc2r and Hsd11b1 genes decreases, which is ultimately aimed at reducing the amount of corticosterone secreted by the adrenal glands, and thus limiting the glucocorticoid response. Thus, chronic stress leads to an imbalance of the activating and stabilizing mechanisms of HPA axis regulation and a possible inadequate response to additional stress stimuli.

Features of reactions to stress in rats with passive-defense behavior after light desynchronosis and physical activity

An assessment was made of hematological parameters of peripheral blood and structural and functional changes in the adrenal glands in stress-unresistant rats (passive-defensive type of behavior in the open field test) after exposure to light deprivation and physical activity during the spring equinox. The experiment showed that light deprivation for 10 days reduces the total number of leukocytes, the absolute content of monocytes, granulocytes, lymphocytes and the level of corticosterone in the peripheral blood compared to the intact group, that was on a natural lighting regime. Histological analysis of the adrenal glands of this group showed, that in the zona fasciculata under such conditions there was nuclear hypertrophy, an increase in the nuclear-cytoplasmic ratio of adrenocorticocytes and a decrease in the size of the zona glomerulosa of the adrenal cortex of rats in relation to the intact group. Physical activity in the form of forced swimming until complete fatigue for 5 days in a row in natural light in stress-unresistant rats did not change the parameters of the peripheral blood of animals, however it led to an increase in the area of the cytoplasm, the nuclear-cytoplasmic ratio, as well as the formation of hypertrophy of the nuclei of adrenocorticocytes in the fascicle adrenal zones, which indicated the preparation of cells for increased synthetic activity. Keeping rats for 10 days in complete darkness before forced swimming every day for 5 days, on the one hand, formed a hypoxic state and exhaustion of the adrenal glands, on the other hand, stabilized the leukocyte pool of peripheral blood compared to similar indicators in intact rats.

Juvenile/Peripubertal Exposure to Omega-3 and Environmental Enrichment Differentially Affects CORT Secretion and Adulthood Stress Coping, Sociability, and CA3 Glucocorticoid Receptor Expression in Male and Female Rats.

In adult rats, omega-3 supplementation through fish oil (FO) and environmental enrichment (EE) have shown beneficial effects on cognition and stress regulation. This study assessed sex-specific effects of FO and EE during adolescence, a period critical for brain maturation, on adulthood coping mechanisms, sociability, and glucocorticoid regulation. An amount of 64 Wistar rats [n = 32/sex; postnatal day (PND) 23] were assigned to supplementation of control soybean oil (CSO) or menhaden fish oil (FO; 0.3 mL/100 g) from PND28 to 47 and exposed to EE or regular cage (RC) housing from PND28 to 58, with their blood corticosterone (CORT) levels being assessed weekly. As adults, exposure to repeated forced swim tests (FSTs; PND90-91) enabled analysis of coping responses, while socioemotional and memory responses were evaluated using the OFT, EPM, SIT, and Y maze tests (PND92-94). Immunohistochemistry determined hippocampal CA1/CA3 glucocorticoid receptor (GR) expression (PND95). CORT secretion gradually increased as the supplementation period elapsed in female rats, while changes were minimal in males. Coping strategies in the FST differed between sexes, particularly in FO-fed rats, where females and males, respectively, favoured floating and tail support to minimise energy consumption and maintain immobility. In the SIT, FO/EE promoted sociability in females, while a CSO diet favoured social recognition in males. Reduced CA3 GR-ir expression was found in FO/RC and CSO/EE rat groups, supporting stress resilience and memory consolidation. Our findings support environment and dietary conditions to exert a sex-specific impact on biobehavioural responses.

Levels of Corticosterone and Glucose in Blood of Rats under Conditions of Chronic Unpredictable Stress of Different Duration

INTRODUCTION: Mammals are almost constantly exposed to a variety of stressors. The changes in the concentration of corticosterone and the level of glucose in blood of animals under such conditions seems relevant for understanding the influence of repeated stress effects on endocrine and metabolic processes. AIM: To study the concentrations of corticosterone and glucose in blood of rats in different time periods of prolonged low-intensity unpredictable stress. MATERIALS AND METHODS: Experiments were carried out on 42 male Wistar rats. Individuals of the experimental groups were subjected to 7-day cycles of alternating stressors using a modified model of chronic unpredictable mild stress with presentation of different stressors. The concentration of corticosterone and glucose in blood was determined at 1, 2, 3 and 4 weeks of observation. RESULTS: A pronounced decrease in corticosterone levels was found in rats at 1 week of stress exposure, followed by a slow recovery by the end of 4th week. Blood glucose level increased at 2 weeks of exposure. CONCLUSION: The data obtained illustrate the specificity of changes in the levels of glucose and corticosterone in the blood of mammals in different time periods of chronic stress. These changes characterize the dysregulation of the integrative physiological systems in relatively early periods of chronic stress with the subsequent development of adaptation in the later stages of repeated stress exposures.

Omega-3 alleviates behavioral and molecular changes in a mouse model of stress-induced juvenile depression

IntroductionDepression is increasingly diagnosed in adolescence, necessitating specific prevention and treatment methods. However, there is a lack of animal models mimicking juvenile depression. This study explores a novel model using ultrasound (US) stress in juvenile mice. MethodsWe employed the US stress model in one-month-old C57/BL6 mice, exposing them to alternating ultrasound frequencies (20–25 kHz and 25–45 kHz) for three weeks. These frequencies correspond to negative and neutral emotional states in rodents and can induce a depressive-like syndrome. Concurrently, mice received either an omega-3 food supplement (FS) containing eicosapentaenoic acid (EPA; 0.55 mg/kg/day) and docosahexaenoic acid (DHA; 0.55 mg/kg/day) or a vehicle. Post-stress, we evaluated anxiety- and depressive-like behaviors, blood corticosterone levels, brain expression of pro-inflammatory cytokines, and conducted metabolome analysis of brain, liver and blood plasma. ResultsUS-exposed mice treated with vehicle exhibited decreased sucrose preference, a sign of anhedonia, a key feature of depression, increased anxiety-like behavior, elevated corticosterone levels, and enhanced TNF and IL-1β gene expression in the brain. In contrast, US-FS mice did not display these changes. Omega-3 supplementation also reduced anxiety-like behavior in non-stressed mice. Metabolomic analysis revealed US-induced changes in brain energy metabolism, with FS increasing brain sphingomyelin. Liver metabolism was affected by both US and FS, while plasma metabolome changes were exclusive to FS. Brain glucose levels correlated positively with activity in anxiety tests. ConclusionChronic omega-3 intake counteracted depressive- and anxiety-like behaviors in a US model of juvenile depression in mice. These effects likely stem from the anti-inflammatory properties of the supplement, suggesting potential therapeutic applications in juvenile depression.

Comparison of Novel and Traditional Bleeding Techniques in Neonatal and Juvenile Mice.

Blood collection is frequently used for neonatal and juvenile mice in toxicology, developmental, and immunology studies and is often a terminal procedure. However, the use of nonterminal blood collection techniques, including the submandibular and the submental collection techniques described for adult mice, may offer opportunities to reduce animal numbers and refine current methods. The use of the submental technique has not been described for neonatal or juvenile mice. In this study, we compared the submental and submandibular blood collection techniques to determine their suitability for use in neonatal and juvenile mice. Male and female CD1 mice, ages 7, 14, 21, and 28 d, were randomized by sex into submental (n = 16), submandibular (n = 16), or control (n = 8) groups. Each mouse was weighed, bled per its assigned group (or only restrained in the case of control mice), and then decapitated without anesthesia for terminal blood collection. Blood collection volume and corticosterone concentrations were measured. The 2 methods showed significant differences in the volume of blood collected at ages 14 and 28, with the submandibular technique yielding significantly higher volumes. No significant differences were detected in corticosterone levels between the 2 techniques based on age or sex. A subset of mice (n = 8, 2 per age group) were bled via submental or submandibular technique and were evaluated 48 h later for gross and histopathologic evidence of trauma. Seven of the 8 mice showed expected inflammation and healing at the collection sites, with 4 mice having embedded strands of fur in the tissue. These data indicate that the submental blood collection is a viable method for nonterminal blood collection method in neonatal and juvenile mice, especially when smaller amounts of blood are needed.

The Concurrent Administration of Dexamethasone and Aldosterone Effectively Mitigates the Pronounced Pro-ulcerogenic Effect of Dexamethasone on the Gastric Mucosa in Rats

We previously established that the effect of dexamethasone (Dex) on the gastric ulceration is time dependent. Administering Dex 1 hour before an ulcerogenic stimulus provides gastroprotection, but extending the interval to 24 hours transforms its effect into a pro-ulcerogenic one. The prolonged maintenance of blood glucose levels induced by Dex, accompanied by catabolic effects, may, in part, account for its pro-ulcerogenic nature (Filaretova et., Inflammopharmacology 2009). Given the evidence that Dex primarily binds to glucocorticoid receptors (GRs), we hypothesized that Dex-induced imbalance in the activation of GRs and mineralocorticoid receptors (MRs) could contribute to the pro-ulcerogenic effect of Dex. We partly confirmed this (Filaretova and Sudalina, FASEB J. 2019). To further validate this hypothesis, we conducted a study to determine whether correcting the imbalance in the activation of GRs and the MRs, induced by Dex, through co-administering Dex with the MR agonist aldosterone (Aldo), can mitigate the pro-ulcerogenic effect of Dex. The effects of separate and combined administration of Dex and Aldo at a dose of 1 mg/kg (i.p.) 1 hour and 24 hours before the onset of ulcerogenic stimulus on the gastric erosions was evaluated in rats. Gastric injury was induced by indomethacin (IM, 35 mg/kg, sc) in preliminary fasted rats. Four hours after IM administration, the rats were decapitated, the stomachs were removed to estimate the erosion area; the adrenal glands, thymus and spleen were remove to estimate their weight, and trunk blood was collected to test the corticosterone and glucose levels. We confirmed the gastroprotective effect of Dex administered 1 hour and the pronounced pro-ulcerogenic effect of Dex administered 24 hours before IM. Aldo itself, administered 1 hour before IM had no effect on the gastric erosions, however, when administered 24 hours before IM, it led to a pro-ulcerogenic effect of IM, but much less pronounced comparing with that of Dex. Co-administration Dex and Aldo 1 hour before IM resulted in the gastroprotection similar to that of Dex alone. Co-administration Dex and Aldo 24 hours before IM effectively mitigates the pronounced pro-ulcerogenic effect of dexamethasone on the gastric mucosa. Dex administration resulted in a sharp decrease in the blood corticosterone level both when administered 1 hour and 24 hours before IM, however, the corticosterone levels in 24 hours were significantly lower than in 1 hour. Aldo itself did not lead to a significant decrease the corticosterone levels neither after 1 hour nor after 24 hours. We confirmed our previous results that Dex administration both 1 hour and 24 hours before IM leads to an increase in blood glucose levels. Administration of Aldo alone did change glucose levels. The effect of the combined administration of Dex and Aldo on glucose levels did not differ from that of Dex alone. 24 hours after Dex administration alone or co-administration Dex with Aldo, pronounced catabolic effects appeared: a decrease in the relative weight of the adrenal glands, thymus and spleen. In conclusion, the concurrent administration of Dex and Aldo effectively mitigates the pronounced pro-ulcerogenic effect of Dex on the gastric mucosa in rats. The results further confirmed our hypothesis. State Program 47 SP “Scientific and Technological Development of the Russian Federation” (2019-2030), 0134-2019-0001. 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.

Association between social dominance hierarchy and PACAP expression in the extended amygdala, corticosterone, and behavior in C57BL/6 male mice

The natural alignment of animals into social dominance hierarchies produces adaptive, and potentially maladaptive, changes in the brain that influence health and behavior. Aggressive and submissive behaviors assumed by animals through dominance interactions engage stress-dependent neural and hormonal systems that have been shown to correspond with social rank. Here, we examined the association between social dominance hierarchy status established within cages of group-housed mice and the expression of the stress peptide PACAP in the bed nucleus of the stria terminalis (BNST) and central nucleus of the amygdala (CeA). We also examined the relationship between social dominance rank and blood corticosterone (CORT) levels, body weight, motor coordination (rotorod) and acoustic startle. Male C57BL/6 mice were ranked as either Dominant, Submissive, or Intermediate based on counts of aggressive/submissive encounters assessed at 12 weeks-old following a change in homecage conditions. PACAP expression was significantly higher in the BNST, but not the CeA, of Submissive mice compared to the other groups. CORT levels were lowest in Submissive mice and appeared to reflect a blunted response following events where dominance status is recapitulated. Together, these data reveal changes in specific neural/neuroendocrine systems that are predominant in animals of lowest social dominance rank, and implicate PACAP in brain adaptations that occur through the development of social dominance hierarchies.

Saikosaponin a alleviates pentylenetetrazol-induced acute epileptic seizures in mouse models of depression by suppressing microglia activation-mediated inflammation

To explore the inhibitory effect of saikosonin a (SSa) on pentylenetetrazol-induced acute epilepsy seizures in a mouse model of depression and explore the mechanism mediating this effect. Male C57BL/6J mouse models of depression was established by oral administration of corticosterone via drinking water for 3 weeks, and acute epileptic seizures were induced by intraperitoneal injection of a single dose of pentylenetetrazole. The effect of intraperitoneal injection of SSa prior to the treatment on depressive symptoms and epileptic seizures were assessed using behavioral tests, epileptic seizure grading and hippocampal morphology observation. ELISA was used to detect blood corticosterone levels of the mice, and RTqPCR was performed to detect the pro- and anti-inflammatory factors. Microglia activation in the mice was observed using immunofluorescence staining. The mouse model of corticosterone-induced depression showed body weight loss and obvious depressive behaviors with significantly increased serum corticosterone level (all P < 0.05). Compared with those with pentylenetetrazole-induced epilepsy alone, the epileptic mice with comorbid depression showed significantly shorter latency of epileptic seizures, increased number, grade and duration of of seizures, reduced Nissl bodies in hippocampal CA1 and CA3 neurons, increased number of Iba1-positive cells, and significantly enhanced hippocampal expressions of IL-1β, IL-10, TNF-α and IFN-γ. Pretreatment of the epileptic mice with SSa significantly prolonged the latency of epileptic seizures, reduced the number, duration, and severity of seizures, increased the number of Nissl bodies, decreased the number of Iba1-positive cells, and reduced the expression levels of IL-1β, IL-10, TNF-α, and IFN-γ in the hippocampus (P < 0.05). Depressive state aggravates epileptic seizures, increases microglia activation, and elevates inflammation levels. SSA treatment can alleviate acute epileptic seizures in mouse models of depression possibly by suppressing microglia activation-mediated inflammation.

Circadian Corticosterone Profile in Laying Hens (Gallus gallus domesticus).

Measurement of blood corticosterone concentrations has been established as an indicator for assessment of acute distress. Therefore, knowledge on physiological fluctuations is required, but previous studies allow little conclusion on daily fluctuations in domestic chickens (Gallus gallus domesticus). To verify the presence of a circadian corticosterone rhythm in socialized chickens, blood samples were taken at four-hour intervals from 12 laying hens kept in groups of four over three days, each. Prior to experiments, hens were adapted to repeated handling for stress reduction. Corticosterone concentration was determined using radioimmunoassay. Blood sampling time and duration were recorded, and audio and video recordings were analyzed to assess the impact of behavior on corticosterone concentrations. Despite individual fluctuations, most hens showed a circadian course with two peaks per day. Statistics revealed a significant peak during the day (between 12:00 p.m. and 04:00 p.m.) and a tendency for a second peak at night (12:00 a.m.). The daily corticosterone peak was not explained by daytime social stress and needs to be seen as an endophenotype. The role of nightly corticosterone production has to be investigated in further studies. There might be a relation between corticosterone and reproduction since the only hen not showing peaks was not laying eggs.

Early-life influenza A (H1N1) infection independently programs brain connectivity, HPA AXIS and tissue-specific gene expression profiles

Early-life adversity covers a range of physical, social and environmental stressors. Acute viral infections in early life are a major source of such adversity and have been associated with a broad spectrum of later-life effects outside the immune system or “off-target”. These include an altered hypothalamus–pituitary–adrenal (HPA) axis and metabolic reactions. Here, we used a murine post-natal day 14 (PND 14) Influenza A (H1N1) infection model and applied a semi-holistic approach including phenotypic measurements, gene expression arrays and diffusion neuroimaging techniques to investigate HPA axis dysregulation, energy metabolism and brain connectivity. By PND 56 the H1N1 infection had been resolved, and there was no residual gene expression signature of immune cell infiltration into the liver, adrenal gland or brain tissues examined nor of immune-related signalling. A resolved early-life H1N1 infection had sex-specific effects. We observed retarded growth of males and altered pre-stress (baseline) blood glucose and corticosterone levels at PND42 after the infection was resolved. Cerebral MRI scans identified reduced connectivity in the cortex, midbrain and cerebellum that were accompanied by tissue-specific gene expression signatures. Gene set enrichment analysis confirmed that these were tissue-specific changes with few common pathways. Early-life infection independently affected each of the systems and this was independent of HPA axis or immune perturbations.

Effects of housing conditions on stress, depressive like behavior and sensory-motor performances of C57BL/6 mice

BackgroundThe effects of housing conditions on animal physiology, behavior or stress are still debated. The aim of this study was to investigate the effects of three different housing systems, individually ventilated cages (IVC), classical small cages with floor surface area of 500 cm2 (CC500) and classical large cages with floor surface area of 800 cm2 (CC800) on body weight, sensory-motor performances, depression-like behavior, plasma corticosterone and brain oxidative stress parameters in C57BL/6 mice. The mice housed in one of the cages from birth to 6 months of age. Hang wire and adhesive removal tests were performed to evaluate somatosensory and motor performances. The extent of depression was determined by the forced swim test. Blood corticosterone levels were measured. In addition, brain malondialdehyde (MDA), total antioxidant status (TAS) and total oxidant status (TOS) levels were analyzed.ResultsThe depression-like behavior of the groups was similar. Although there were no significant differences in hang wire test among groups, CC500 group required longer durations in adhesive removal test. The body weight and plasma corticosterone levels of CC800 group were significantly higher than other groups. The oxidative stress parameters were highest in CC500 cage.ConclusionsOur study showed that the least stressful housing condition was IVC cage systems. Interestingly, the number of mice in the classical cages had a significant effect on stress levels and sensory-motor performance.

Examination of empathy-like behaviour in nicotine-preferring rat lines

Aim Addiction is an important global health issue, impacting also addicts environment and society. Empathy plays crucial role in establishing successful social relationships and is a fundamental component of social life. The aim of this study is to investigate how nicotine preferring (NP) strain and oral forced nicotine administration affects empathy-like behaviour in rats, with gender differences. Materials and Methods Sprague-Dawley NP rats (10 males/10 females) and wild-type control rats (10 males/10 females) were used. Behavioural tests were administered to all rats before and after oral forced nicotine administration. The behavioural tests were completed in the fourth week of nicotine administration. Anxiety levels that could affect empathy-like behaviour were evaluated with open field, elevated plus maze tests and with blood cortisol levels. Oxytocin receptor and arginine vasopressin (AVP) levels, which have been shown to be related to empathy-like behaviour, were examined in the prefrontal cortex and amygdala regions using the enzyme-linked immunoassay method. Results It was observed that males from the NP strain showed less empathy-like behaviour than all other groups, and nicotine administration did not cause a significant change in the results. Higher levels of locomotor activity (LA) were found in control females than in all other groups. Blood nicotine and corticosterone levels were higher in NP rats. No significant differences were found in AVP and oxytocin receptor levels in the prefrontal cortex and amygdala. Conclusions It was found that coming from an addicted strain particularly reduces empathy-like behaviour in males.

The Level of Sex Hormones and Corticosterone in Female Rats during Modeling of Visceral Obesity, Subsequent Physical Activity, and Normalization of the Diet.

The effects of diet-induced visceral obesity and non-drug options of its correction on the level of sex hormones and corticosterone were evaluated in 84 female Wistar rats. During stage I, the rats received either a standard diet (STD) or a high-calorie diet (HCD) for 8 weeks. During stage II, the animals were divided into subgroups depending on obesity correction: without correction (STD control and HCD), transition from HCD to STD (HCD/STD) and/or physical activity (treadmill exercise) for the next 8 weeks (HCD/STD+exercise, STD+exercise, and HCD+exercise). Diet-induced visceral obesity resulted in hyperandrogenization and increased blood corticosterone levels in females. Transition from HCD to STD regardless of physical activity led to normalization of testosterone level and, accordingly, to return to the functional norm of estrogen-androgen balance. The positive effect of moderate physical activity on hormonal status is realized only against the background of a balanced diet or during the transition from HCD to STD.

Age-dependent effects of acute stress on the behavior, blood parameters, immunity, and enteric nerves of mice

The impact of stress on mental and digestive health has been extensively studied, with chronic stress being associated with various disorders. However, age-related differences in the response to acute stress, both behaviorally and physiologically, remain poorly understood. Therefore, this study aimed to develop a model to detect transient stress in mice of different ages. The stressor employed in our experiments was a restraint stress procedure, where mice were subjected to brief periods of immobilization to induce an acute stress response. Male C3H/HeN mice aged 3, 6, 12, and 30 weeks were subjected to acute restrain stress (ARS) by being placed in a 50 ml conical centrifuge tube for 15 min. Subsequently, their behavior, organ tissues, hematological parameters, cortisol concentration, and immune responses were assessed. Following ARS, the increased in time and entries into the center by the 12-week-old mice following stress. In comparison to mice of other ages, those aged 6 weeks demonstrated notable elevations in erythrocytes, platelets, hemoglobin, and hematocrit, all of which were influenced by the time-dependent changes and the recovery process of ARS. Blood corticosterone levels were substantially elevated in all age groups after ARS. Furthermore, ARS induced a notable increase in leukocytes, basophils, residential macrophages, and CD4+ T cells in all age groups except for 3-week-old mice. However, the number of monocyte-derived macrophages and CD8+ T cells did not change significantly. Additionally, mice aged 3 and 6 weeks demonstrated an increase in GFAP+ cells following ARS, whereas NeuN+ cells decreased across all ages. These results suggest that ARS has varying effects on the behavior, cortisol concentration, and quantity of blood cells as well as hepatic immune cells in mice of different ages. These age-dependent responses shed light on the complex interplay between stress and physiological systems and contribute to the broader understanding of stress-related diseases.

Early life adversity reduces affiliative behavior with a stressed cagemate and leads to sex-specific alterations in corticosterone responses in adult mice

Experiencing early life adversity (ELA) alters stress physiology and increases the risk for developing psychiatric disorders. The social environment can influence dynamics of stress responding and buffer and/or transfer stress across individuals. Yet, the impact of ELA on sensitivity to the stress of others and social behavior following stress is unknown. Here, to test the impact of ELA on social and physiological responses to stress, circulating blood corticosterone (CORT) and social behaviors were assessed in adult male and female mice reared under limited bedding and nesting (LBN) or control conditions. To induce stress, one cagemate of a pair-housed cage underwent a footshock paradigm and was then returned to their unshocked partner. CORT was measured in both groups of mice 20 or 90 min after stress exposure, and social behaviors were recorded and analyzed. ELA rearing influenced the CORT response to stress in a sex-specific manner. In males, both control and ELA-reared mice exhibited similar stress transfer to unshocked cagemates and similar CORT dynamics. In contrast, ELA females showed a heightened stress transfer to unshocked cagemates, and sustained elevation of CORT relative to controls, indicating enhanced stress contagion and a failure to terminate the stress response. Behaviorally, ELA females displayed decreased allogrooming and increased investigative behaviors, while ELA males showed reduced huddling. Together, these findings demonstrate that ELA influenced HPA axis dynamics, social stress contagion and social behavior. Further research is needed to unravel the underlying mechanisms and long-term consequences of ELA on stress systems and their impact on behavioral outcomes.

Housing conditions affect enterocyte death mode and turnover rate in mouse small intestine

Small intestinal enterocytes are continuously renewed. Shedding/death of enterocytes involves receptor-interacting protein kinase 1 (RIPK1)-dependent (but RIPK3-independent) necrotic death, but the regulatory mechanism of the processes is not fully understood. Here, we show that mouse housing conditions, such as the type of bedding material and the presence or absence of a Shepherd Shack, affect enterocyte turnover rate and determine whether enterocyte shedding/death is RIPK1-independent or -dependent. Mice housed with ALPHA-dri (αDri, hard paper chip) bedding material without a Shepherd Shack had a higher, largely RIPK1-dependent enterocyte turnover rate and higher blood corticosterone levels, suggesting the involvement of minor stress, whereas mice housed with αDri plus a Shepherd Shack or with Soft Chip had a lower, RIPK1-independent turnover rate and lower blood corticosterone levels. Corticosterone administration to a small intestine culture derived from mice housed with αDri plus a Shepherd Shack or with Soft Chip increased enterocyte shedding/death and turnover. By using kinase inhibitors and knockout mice, we showed that the switch from RIPK1-independent to RIPK1-dependent enterocyte shedding/death and turnover involves suppression of TANK-binding kinase 1. Our results demonstrate that housing conditions may cause minor stress, which alters the mode of enterocyte shedding/death and enterocyte turnover rate in mice.