Serum Corticosterone Research Articles

Influence of Diet on Reproducible Corticosterone Levels in a Mouse Model of Maternal Separation with Early Weaning.

Maternal separation with early weaning (MSEW) is a popular early life stress (ELS) model in rodents, which emulates childhood neglect through scheduled mother-offspring separation. Although variations of ELS models, including maternal separation and MSEW, have been published for the mouse species, the reported results are inconsistent. Corticosterone is considered the main stress hormone involved in regulating stress responses in rodents-yet generating a robust and reproducible corticosterone response in mouse models of ELS has been elusive. Considering the current lack of standardization for MSEW protocols, these inconsistent results may be attributed to variations in model methodologies. Here, we compared the effects of select early wean diet sources-which are the non-milk diets used to complete early weaning in MSEW pups-on the immediate stress phenotype of C57BL/6J mice at postnatal day 21. Non-aversive handling was an integral component of our modified MSEW model. The evaluation of body weight and serum corticosterone revealed the early wean diet to be a key variable in the resulting stress phenotype. Interestingly, select non-milk diets facilitated a stress phenotype in which low body weight was accompanied by significant corticosterone elevation. Our data indicate that dietary considerations are critical in MSEW-based studies and provide insight into improving the reproducibility of key stress-associated outcomes as a function of this widely used ELS paradigm.

Effects of blood extraction and ecophysiological experiments on stress in adult males of Liolaemus attenboroughi.

Stress during laboratory experiments can affect the outcomes of ecophysiological studies. The serum corticosterone concentration (CORT), the leukocyte profile, heterophil/lymphocyte ratio (H/L), and the presence of blood endoparasites were analyzed as a proxy of stress and immunological state in adult males of the lizard Liolaemus attenboroughi, endemic to Patagonia, Argentina. The results of the ecophysiological variables (preferred temperature, running speed, locomotor endurance, and body condition index, BCI) were analyzed in relation to stress indicators obtained from blood samples taken at three different times: at capture, and on the third and seventh days in the laboratory. Males at capture showed a high percentage of lymphocytes and heterophils and a low of basophils, monocytes, and eosinophils. Haemogregorina-type endoparasites have been recorded in the genus Liolaemus for the first time. The proportion of infected males remained stable during captivity; however, these males showed higher CORT levels, increased percentages of basophils, and decreased percentages of lymphocytes. There was a significant increment in CORT and H/L, and a decrease in BCI during laboratory experiments, compared with baseline values at capture. The performance was not related to the CORT or the repeated blood sampling. The BCI decreased, possibly due to energy reserve mobilization caused by acute stress. This study shows that blood extraction and ecophysiological experiments over 7 days have a minor effect on the stress indicators used.

Methane-rich saline ameliorates depressive-like behaviors during chronic unpredictable mild stress (CUMS).

Depression, considered the most prevalent neuropsychiatric disorder, is multifactorial and complex. Oxidative stress and inflammation significantly contribute to its etiology. Conversely, methane, a novel therapeutic gas, has demonstrated efficacy in enhancing tissue resilience against ischemic injuries and inflammation. In this study, we investigated the effect of methane-rich saline (MRS) on depression using the chronic unpredictable mild stress (CUMS) model. Depressed rats received MRS treatment, and depression-like behaviors and cognitive function were assessed through sucrose preference, open field, forced swimming, and Morris water maze tests. Additionally, we measured serum corticosterone levels, antioxidant enzyme activity, hippocampal malondialdehyde (MDA), and TNFα levels, and investigated histological changes in the hippocampus. Our findings revealed that MRS significantly ameliorated Depressive-like behaviors and cognitive impairment. Furthermore, MRS administration regulated serum corticosterone levels and also MRS reduced hippocampal lipid peroxidation, TNFα, and hippocampus tissue damage. MRS likely exerts its effects by reducing oxidative stress and inflammatory factors and modulating the function of the hypothalamus-pituitary-adrenal (HPA) axis. These results demonstrate the protective effects of MRS on the hippocampus in CUMS animals.

Male-biased vulnerability of mouse brain tryptophan/kynurenine and glutamate systems to adolescent exposures to concentrated ambient ultrafine particle air pollution

Air pollution (AP) exposures have been associated with numerous neurodevelopmental and psychiatric disorders, including autism spectrum disorder, attention deficit hyperactivity disorder and schizophrenia, all male-biased disorders with onsets from early life to late adolescence/early adulthood. While prior experimental studies have focused on effects of AP exposures during early brain development, brain development actually extends well into early adulthood. The current study in mice sought to extend the understanding of developmental brain vulnerability during adolescence, a later but significant period of brain development and maturation to the ultrafine particulate (UFPs) component of AP, considered its most reactive component. Additionally, it examined adolescent response to UFPs when preceded by earlier developmental exposures, to ascertain the trajectory of effects and potential enhancement or mitigation of adverse consequences. Outcomes focused on shared features associated with multiple neurodevelopmental disorders. For this purpose, C57Bl/6 J mice of both sexes were exposed to ambient concentrated UFPs or filtered air from PND (postnatal day) 4–7 and PND10–13, and again at PND39–42 and 45–49, resulting in 3 exposure postnatal/adolescent treatment groups per sex: Air/Air, Air/UFP, and UFP/UFP. Features common to neurodevelopmental disorders were examined at PND50. Mass exposure concentration from postnatal exposure averaged 44.34 μg/m3 and the adolescent exposure averaged 49.18 μg/m3. Male brain showed particular vulnerability to UFP exposures in adolescence, with alterations in frontal cortical and striatal glutamatergic and tryptophan/serotonergic neurotransmitters and concurrent reductions in levels of astrocytes in corpus callosum and in serum cytokine levels, with combined exposures resulting in significant reductions in corpus callosum myelination and serum corticosterone. Reductions in serum corticosterone in males correlated with reductions in neurotransmitter levels, and reductions in striatal glutamatergic function specifically correlated with reductions in corpus callosum astrocytes. UFP-induced changes in neurotransmitter levels in males were mitigated by prior postnatal exposure, suggesting potential adaptation, whereas reductions in corticosterone and in corpus callosum neuropathological effects were further strengthened by combined postnatal and adolescent exposures. UFP-induced changes in females occurred primarily in striatal dopamine systems and as reductions in serum cytokines only in response to combined postnatal and adolescent exposures. Findings in males underscore the importance of more integrated physiological assessments of mechanisms of neurotoxicity. Further, these findings provide biological plausibility for an accumulating epidemiologic literature linking air pollution to neurodevelopmental and psychiatric disorders. As such, they support a need for consideration of the regulation of the UFP component of air pollution.

Transcriptome signatures of the medial prefrontal cortex underlying GABAergic control of resilience to chronic stress exposure.

Analyses of postmortem human brains and preclinical studies of rodents have identified somatostatin (SST)-positive interneurons as key elements that regulate the vulnerability to stress-related psychiatric disorders. Conversely, genetically induced disinhibition of SST neurons or brain region-specific chemogenetic activation of SST neurons in mice results in stress resilience. Here, we used RNA sequencing of mice with disinhibited SST neurons to characterize the transcriptome changes underlying GABAergic control of stress resilience. We found that stress resilience of male but not female mice with disinhibited SST neurons is characterized by resilience to chronic stress-induced transcriptome changes in the medial prefrontal cortex. Interestingly, the transcriptome of non-stressed stress-resilient male mice resembled the transcriptome of chronic stress-exposed stress-vulnerable mice. However, the behavior and the serum corticosterone levels of non-stressed stress-resilient mice showed no signs of physiological stress. Most strikingly, chronic stress exposure of stress-resilient mice was associated with an almost complete reversal of their chronic stress-like transcriptome signature, along with pathway changes indicating stress-induced enhancement of mRNA translation. Behaviorally, the mice with disinhibited SST neurons were not only resilient to chronic stress-induced anhedonia - they also showed an inversed anxiolytic-like response to chronic stress exposure that mirrored the chronic stress-induced reversal of the chronic stress-like transcriptome signature. We conclude that GABAergic dendritic inhibition by SST neurons exerts bidirectional control over behavioral vulnerability and resilience to chronic stress exposure that is mirrored in bidirectional changes in expression of putative stress resilience genes, through a sex-specific brain substrate.

P-005 Could early life stress be related to the hippo signaling pathway in rat testis?

Abstract Study question Is there a change in the Hippo signaling pathway in the rat testis exposed to early life stress for 14 days in the postnatal period? Summary answer It was observed that the YAP and p-YAP signaling levels decreased in rats exposed to early-life stress when compared to the control groups. What is known already Hippo signaling pathway has been reported that it participates in many events such as cell division, proliferation, differentiation, and programmed cell death. YAP (Yes-Associated Protein) and p-YAP (phospho-YAP) are the main components of this pathway. Deterioration in sperm production and decreasing the serum testosterone levels were observed in rats exposed to stress stimulation in literature. However, the molecular mechanisms underlying these problems in the male reproductive system caused by stress have not yet been elucidated. Study design, size, duration 180-minute maternal deprivation and isolation model was applied to the early-life stress group (ELS) every day between the 1st and 14th postnatal day. Tail blood was collected before and after stress conditions on 14th postnatal day. Serum corticosterone levels were detected. On the 14th day, the control and ELS groups were sacrificed and the testicles were placed in appropriate fixatives. Participants/materials, setting, methods In total of 10 newborn Wistar albino male rats were used. Two groups were formed as Control (n = 5) and ELS (n = 5) groups. On postnatal 14th day, the groups were sacrificed. For immunohistochemical analyses, testis were taken into buffered formalin, paraffin blocks were made and the sections were taken. ELISA kit was used for serum corticosterone level. Main results and the role of chance The post-stress serum corticosterone levels of the ELS group were found to be significantly higher compared to the control group (p < 0.05). At least 60 seminiferous tubules were evaluated for immunohistochemical analyzes in the testis. H-score evaluation was applied. It was determined that YAP and p-YAP expressions decreased in the ELS group when compared to control group (p < 0.05) on the 14th postnatal day when mitosis and proliferation are high in testis cell groups. In addition the seminiferous tubule diameter was smaller in the experimental group. As we conducted in the literature research, stress conditions were generally based on adult subjects. There are insufficient data on the effects of stress on the testis in the early postnatal periods. This suggests that stress created in the early period may cause various defects as the cells enter the adult period. Limitations, reasons for caution This study was performed in vivo rat model in the postnatal 14th days. In further studies, groups including the adulthood period will be added. Wider implications of the findings After the 14th day of the postnatal period day, the blood-testis barrier is formed and spermatogenesis processes begin. Any defect that occurs in this day can cause problems in sperm development. This study can bring a new perspective to researching the effects of stress on testis in prepubertal period. Trial registration number not applicable

Interrogating the estrogen-mediated regulation of adrenocortical Klotho expression using ovariectomized albino rat model exposed to repeated restraint stress.

Reproductive aging is associated with altered stress response and many other menopausal symptoms. Little is known about the adrenal expression of the anti-aging protein Klotho or how it is modulated by estrogen in ovariectomized stressed rats. Fifty-six Wistar female rats were assigned into seven equal groups. Sham-operated (Sham), sham stressed (Sham/STS), ovariectomized (OVR), ovariectomized stressed (OVR/STS), ovariectomized stressed rosiglitazone-treated (OVR/STS/R), ovariectomized stressed estrogen-treated (OVR/STS/E), and ovariectomized stressed estrogen/GW9662 co-treated (OVR/STS/E/GW) groups. All stressed rats were subjected daily to a one-hour restraint stress test for 19days.At the end of the experiment, blood was collected for serum corticosterone (CORT) analysis. Adrenal tissues were obtainedand prepared for polymerase chain reaction (PCR) assay, hematoxylin and eosin (H&E), immunohistochemistry-based identification of Klotho and PPAR-γ, and Oil Red O (ORO) staining. The rise in serum CORT was negligible in the OVR/STS group, in contrast to the Sham/STS group. The limited CORT response in the former group was restored by estrogen and rosiglitazone and blocked by estrogen/GW9226 co-administration. ORO-staining revealed a more evident reduction in the adrenal fat in the OVR/STS group, which was reversed by estrogen and counteracted by GW. Also, there was a comparable expression pattern of Klotho and PPAR-γ in the adrenals. The adrenal Klotho decreased in the OVR/STS group, but was reversed by estrogen treatment. GW9226/estrogen co-treatment interfered with the regulatory effect of estrogen on Klotho. The study suggested modulation of the adrenal Kotho expression by estrogen, in the ovariectomized rats subjected to a restraint stress test. This estrogen-provided adrenal protection might be mediated by PPAR-γ activation.

Kamishoyosan Normalizes Dendritic Spine Morphology in the Medial Prefrontal Cortex by Regulating microRNA-18 and Glucocorticoid Receptor Expressions in Postmenopausal Chronic Stress-Exposed Mice.

Kamishoyosan (KSS), a traditional Japanese Kampo medicine, is widely used to treat neuropsychiatric symptoms in perimenopausal and postmenopausal women. We aimed to elucidate the functional mechanisms underlying KSS-mediated reduction of stress response behaviors and neuropsychological symptoms in perimenopausal and postmenopausal women. Female mice were bilaterally ovariectomized (OVX) at the age of 12 weeks and exposed to chronic water immersion and restraint stress for three weeks. Among them, mice in the OVX+stress+KSS group were fed chow containing KSS from one week before exposure to chronic stress until the end of the experiment. Firstly, we performed a marble burying test and measured serum corticosterone levels to assess irritability and stress conditions. Next, we examined whether KSS affects microRNA-18 (miR-18) and glucocorticoid receptor (GR) protein expression, as well as the basal dendritic spine morphology of pyramidal neurons in the medial prefrontal cortex (mPFC) of postmenopausal chronic stress-exposed mice. Analyzed data were expressed as mean ± standard deviation. Tukey's post hoc test, followed by analysis of variance (ANOVA), was used for among-group comparisons. KSS administration normalized chronic stress-induced unstable emotion-like behavior and upregulated plasma corticosterone levels. Furthermore, KSS ameliorated GR protein expression by downregulating miR-18 expression in the mPFC and recovered the immature morphological changes in spine formation of pyramidal neurons in the mPFC of OVX mice following chronic stress exposure. KSS administration in postmenopausal chronic stress-exposed mice exerted anti-stress effects and improved the basal dendritic spine morphology of pyramidal neurons by regulating miR-18 and glucocorticoid receptor expression in the mPFC.

Assessment of Serum Levels of Phosphate and Corticosterone as Possible Biomarkers for Early Diagnosis of Parkinson’s Disease in Rats with 6-OHDA-Induced Parkinson

Background: Early diagnosis of Parkinson›s disease can play an important role in improving its prognosis. Due to controversies about the serum level of corticosterone and phosphate in parkinsonian rats, this study was designed to measure and evaluate the levels of corticosterone and phosphate as possible biomarkers of early diagnosis in rats with 6-OHDA-induced parkinsonism. Methods: Forty rats were divided into three groups: control (n=10), sham (n=10), and 6-OHDA (n=20). The rats in the 6-OHDA and sham groups underwent stereotaxic surgery to be injected with 6-OHDA and its carrier into their medial forebrain bundle (MFB). Apomorphine-induced rotational and cylinder tests were done to examine parkinsonism progression and sensory-motor function. Corticosterone and phosphate serum levels were measured in the serum and striatum. Results: Net contralateral rotations and asymmetry scores in the fourth, sixth, and eighth weeks after surgery compared with the second week showed a gradual increase in the 6-OHDA group. The serum levels of corticosterone were 90±13 before surgery, and they declined to 88±36 and 55±9 ng/L in the second and eighth weeks after surgery, respectively. The serum levels of phosphate were 6±0.22 before surgery, and they decreased to 5.2±0.13 and 5±0.12 mg/dl in the second and eighth weeks after surgery, respectively. The serum levels of phosphate and corticosterone remained relatively unchanged in the sham and control groups. Conclusion: In conclusion, the progressive death of dopaminergic neurons is accompanied by decreased serum corticosterone and phosphate levels. Thus, the serum level of corticosterone can be used as a biomarker in diagnosing Parkinson’s disease. In contrast, serum phosphate levels were still within the normal range and cannot be used as a biomarker.

Protein Tyrosine Phosphatase Receptors N and N2 Control Pituitary Melanotroph Development and POMC Expression.

The neuroendocrine marker genes Ptprn and Ptprn2 encode protein tyrosine phosphatase receptors N and N2, 2 members of protein tyrosine phosphatase receptors void of enzymatic activity, and whose function and mechanism of action have not been elucidated. To explore the role(s) of Ptprn and Ptprn2 on the hypothalamic-pituitary-adrenal axis, we used mice in which both genes were knocked out (DKO). The focus in this study was on corticotrophs and melanotrophs from the anterior and intermediate lobes of the pituitary gland, respectively. In both sexes, DKO caused an increase in the expression of the corticotroph/melanotroph genes Pomc and Tbx19 and the melanotroph-specific gene Pax7. We also found in vivo and in vitro increased synthesis and release of beta-endorphin, alpha-melanocyte-stimulating hormone, and ACTH in DKO mice, which was associated with increased serum corticosterone levels and adrenal mass. DKO also increased the expression of other melanotroph-specific genes, but not corticotroph-specific genes. The dopaminergic pathway in the hypothalamus and dopaminergic receptors in melanotrophs were not affected in DKO mice. However, hyperplasia of the intermediate lobe was observed in DKO females and males, accompanied by increased proopiomelanocortin immunoreactivity per cell. These results indicate that protein tyrosine phosphatase receptor type N contributes to hypothalamic-pituitary-adrenal function by being involved in processes governing postnatal melanotroph development and Pomc expression.

Diosgenin reverses posttraumatic stress disorder in mice by augmenting neurochemical release and inhibiting HPA axis dysfunction, oxidative stress, and neuroinflammation

Post-traumatic stress disorder (PTSD) is a mental disorder linked to neurochemical, hypothalamic-pituitary-adrenal (HPA)-axis dysregulations, inflammatory and pro-oxidant challenges in response to traumatic events. It is one of the leading causes of neurocognitive declines, hence prompting the need for a pharmacological intervention. However, the impact of diosgenin, a naturally occurring steroidal saponin with adaptogenic-like action, on PTSD-induced neuropsychiatric disturbances and its underlying mechanisms are unknown. In this study, we investigated the outcome of diosgenin treatment in a multimodal traumatic, single prolonged stress (SPS)-induced PTSD in mice. Following the SPS-induced 7 days of PTSD, mice (n = 9) were thereafter treated with diosgenin (25 and 50 mg/kg) or fluoxetine (10 mg/kg) orally from days 8–20 (14 days). Locomotory, cognitive-, depressive- and anxiety-like behaviors were investigated. We assayed for changes in adrenal weight, serum glucose and corticosterone concentrations. Neurochemical, inflammatory, oxido-nitrergic dysfunctions and monoamine oxidase-B and acetylcholinesterase activities, were measured in the striatum, prefrontal-cortex and hippocampus. The results revealed that the SPS challenge inhibited locomotor, spatial/non-spatial memory functions, increased anxiety and depressive-like features, which were reversed by diosgenin. Diosgenin reduced SPS-induced increased monoamine oxidase-B, acetylcholinesterase activities, TNF-α, IL-6, malondialdehyde and nitrite levels in the striatum, prefrontal-cortex and hippocampus. Antioxidants such as glutathione, superoxide-dismutase, and catalase levels in SPS-mice brains were increased by diosgenin. Moreover, diosgenin attenuated SPS-induced hyper-HPA-axis mediation of PTSD by decreasing serum corticosterone, glucose levels and adrenal gland hypertrophy. Herewith, we suggest that diosgenin convenes adaptogenic-like protection against mice exposed to PTSD by enhancing antioxidant machinery, neurochemical modulations, and inhibition of oxido-nitrergic, inflammatory, and HPA-axis dysfunctions.

PERK inhibitor (ISRIB) improves depression-like behavior by inhibitions of HPA-axis over-activation in mice exposed to chronic restraint stress

Stressful life event is closely associated with depression, thus strategies that blunt or prevent the negative effect stress on the brain might benefits for the treatment of depression. Although previous study showed the role of protein kinase R (PKR)-like ER kinase (PERK) in inflammation related depression, its involvement in the neuropathology of chronic stress induced depression is still unknown. We tried to explore whether block the PERK pathway would alleviate the animals’ depression-like behavior induced by chronic restraint stress (CRS) and investigate the underlying mechanism. The CRS-exposed mice exhibited depression-like behavior, including anhedonia in the sucrose preference test (SPT), and increased immobility time in tail suspension test (TST) and forced swim test (FST). ISRIB administration for 2 weeks significantly improved the depression-like behavior in male mice exposed to CRS, which was manifested by markedly increasing the sucrose preference and reducing the immobility time in the FST and TST. However, we observed that exposure to the same dose of ISRIB in CRS female mice only showed improved anhedonia-like deficits,leaving unaltered improvement in the FST and TST. Mechanically, we found that ISRIB reversed the hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, indicating decreased levels of serum corticosterone, reduced hippocampal glucocorticoidreceptor (GR) expression and expression of FosB in hypothalamic paraventricularnucleus (PVN), which was accompanied by preserved hippocampal neurogenesis. The present findings further expand the potential role of ER stress in depression and provide important details for a therapeutic path forward for PERK inhibitors in mood disorders.

Effects of different doses of dexmedetomidine combined with sufentanil in intravenous controlled analgesia after Salter osteotomy in children.

This study aimed to investigate the effect of different doses of dexmedetomidine combined with sufentanil on postoperative analgesia in developmental hip dislocation in children after Salter osteotomy. The clinical data of 98 children with developmental hip dislocation, who underwent Salter osteotomy in our center between January 2020 and February 2023, were selected. The children were randomly divided into four groups based on the application of patient-controlled intravenous analgesia (sufentanil + granisetron ± dexmedetomidine). All children received 1 µg/kg/day of sufentanil and 3 mg of granisetron. Group A did not receive dexmedetomidine, and Groups B, C, and D received 0.5, 0.75, and 1.0 µg/kg/day of dexmedetomidine, respectively. The pain indicators and immune factor levels of children in each group were compared. The heart rate (HR) and respiratory rate (RR) 2 h after operation in Groups C and D were significantly lower than those in Groups A and B (P < 0.05). The pain scores decreased over time after treatment in all groups. When compared at the same time point, children in Group D had the lowest pain scores, which were significantly lower than the other three groups (P < 0.05). The total consumption of sufentanil in Groups C and D was significantly lower than that in Group A (P < 0.05). On the first day after surgery, the children in Group D had lower levels of serum adrenocorticotropic hormone, interleukin-6, and corticosterone than those in Group A (P < 0.05). Administration of 1.0 µg/kg/day of dexmedetomidine combined with sufentanil in intravenous controlled analgesia after Salter osteotomy for developmental hip dislocation in children has a better analgesic effect, less consumption of sufentanil, and low incidence of opioid adverse reactions.

Reduced hepatic AdipoR2 by increased glucocorticoid mediates effect of psychosocial stress to elevate serum cholesterol

Understanding the effects of psychosocial stress on serum cholesterol may offer valuable insights into the relationship between psychological disorders and endocrine diseases. However, these effects and their underlying mechanisms have not been elucidated yet. Here we show that serum corticosterone, total cholesterol and low-density lipoprotein cholesterol (LDL-C) are elevated in a mouse model of psychosocial stress. Furthermore, alterations occur in AdipoR2-mediated AMPK and PPARα signaling pathways in liver, accompanied by a decrease in LDL-C clearance and an increase in cholesterol synthesis. These changes are further verified in wild-type and AdipoR2 overexpression HepG2 cells incubated with cortisol and AdipoR agonist, and are finally confirmed by treating wild-type and hepatic-specific AdipoR2 overexpression mice with corticosterone. We conclude that increased glucocorticoid mediates the effects of psychosocial stress to elevate serum cholesterol by inhibiting AdipoR2-mediated AMPK and PPARα signaling to decrease LDL-C clearance and increase cholesterol synthesis in liver.

The effect of late-life environmental enrichment on stress and anxiety: The role of sex and age-related differences in coping with aversive stimuli

Anxiety significantly diminishes the quality of life in older adults, and the drugs used for its treatment often come with risky side effects. Non-pharmacological protocols could be valuable, but more research is needed in this area. Environmental enrichment induces positive effects on anxiety-like behavior in young and adult animals; whether the same happens in aged animals is still elusive. The aged brain undergoes changes that contribute to make it “fragile” and consequently even mild, potentially positive stimuli can trigger dyshomeostasis, worsening rather than ameliorating functioning. Here, by combining behavioral analysis and measurement of serum and brain corticosterone levels, we show that late-life environmental enrichment can induce eustress or distress, depending on sex and hypothalamic-pituitary-adrenal axis function. These findings pave the way for optimizing outcomes and minimizing undesired effects in the clinical setting, underscoring the need to overcome the limits of gender medicine and emphasizing the crucial role of individually tailored therapies.

Anxiolytic effects of Enterococcus faecalis 2001 on a mouse model of colitis

Ulcerative colitis (UC) is a refractory inflammatory bowel disease, which is known to cause psychiatric disorders such as anxiety and depression at a high rate in addition to peripheral inflammatory symptoms. However, the pathogenesis of these psychiatric disorders remains mostly unknown. While prior research revealed that the Enterococcus faecalis 2001 (EF-2001) suppressed UC-like symptoms and accompanying depressive-like behaviors, observed in a UC model using dextran sulfate sodium (DSS), whether it has an anxiolytic effect remains unclear. Therefore, we examined whether EF-2001 attenuates DSS-induced anxiety-like behaviors. Treatment with 2% DSS for seven days induced UC-like symptoms and anxiety-like behavior through the hole-board test, increased serum lipopolysaccharide (LPS) and corticosterone concentration, and p-glucocorticoid receptor (GR) in the prefrontal cortex (PFC), and decreased N-methyl-d-aspartate receptor subunit (NR) 2A and NR2B expression levels in the PFC. Interestingly, these changes were reversed by EF-2001 administration. Further, EF-2001 administration enhanced CAMKII/CREB/BDNF-Drebrin pathways in the PFC of DSS-treated mice, and labeling of p-GR, p-CAMKII, and p-CREB showed colocalization with neurons. EF-2001 attenuated anxiety-like behavior by reducing serum LPS and corticosterone levels linked to the improvement of UC symptoms and by facilitating the CAMKII/CREB/BDNF-Drebrin pathways in the PFC. Our findings suggest a close relationship between UC and anxiety.

Environmental enrichment and the combined interventions of EE and metformin enhance hippocampal neuron survival and hippocampal-dependent memory in type 2 diabetic rats under stress through the BDNF-TrkB signaling pathways

BackgroundType 2 diabetes (T2D) with depression causes severe cognitive impairments. The devastating conditions will further compromise the overall quality of life. The overconsumption of high-fat and high-sucrose (HFS) diet is one of the modifiable risk factors for T2D, depression, and cognitive impairments. Thus, it is essential to identify effective therapeutic strategies to overcome the cognitive impairments in T2D with depression. We proposed environmental enrichment (EE) which encompasses social, cognitive, and physical components as the alternative treatment for such impairments. We also investigated the potential neuroprotective properties of the antidiabetic drug metformin. This study aimed to investigate the effects of EE and metformin interventions on hippocampal neuronal death, and hippocampal-dependent memory impairment in T2D rats under stress. MethodsThirty-two male rats (200–250 g) were divided into four groups: C group (standard diet + conventional cage), DS group [HFS-induced T2D + restraint stress (RS)], DSE group [HFS-induced T2D + RS + EE] and DSEM group [HFS + RS + EE + metformin]. Serum corticosterone (CORT) was measured to evaluate stress levels. The serum Free Oxygen Radicals Testing (FORT) and Free Oxygen Radicals Defence Test (FORD) were measured to evaluate the systemic oxidative status (OS). Serum brain-derived neurotrophic factor (BDNF) and T-maze tasks were performed to evaluate cognitive functions. Rats were humanely sacrificed to collect brains for histological, morphometric, and hippocampal gene expression studies. ResultsThe CORT and the serum FORT levels in the DSE and DSEM groups were lower than in the DS group. Meanwhile, the serum BDNF, T-maze scores, histological, and morphometric analysis were improved in the DSE and DSEM groups than in the DS group. These findings supported that EE and the combined interventions of EE and metformin had neuroprotective properties. The hippocampal gene expression analysis revealed that the DSE and DSEM groups showed improved regulation of BDNF-TrkB signalling pathways, including the BDNF/TrkB binding, PI3K – Akt pathway, Ras–MAPK pathway, PLCγ–Ca2+ pathway, and CREB transcription. ConclusionEE and the combined interventions of EE and metformin improved hippocampal neuron survival and hippocampal-dependent memory in T2D rats under stress by enhancing gene expression regulation of neurogenesis and synaptic plasticity.

Impact of social isolation on corticosterone release and recovery after stroke in aged rats: A behavioral and biochemical analysis

Social isolation (SI) after stroke reduces recovery. The aim of this study was to evaluate the effects of SI on corticosterone release and recovery after stroke in aged rats. A total of 64 male Wistar rats (aged 24 months) were used in the present study. All rats were housed in pairs for two weeks. After two weeks, rats were randomly assigned to one of four groups: (1) rats underwent sham surgery and kept socially isolated (control/social isolated (CO/SI) group); (2) rats underwent sham surgery and kept pair housed (control/pair housed (CO/PH) group); (3) rats underwent middle cerebral artery occlusion (MCAO) surgery and kept socially isolated (stroke/isolated (ST/SI) group); (4) rats underwent MCAO surgery and kept pair housed (stroke/pair housed (ST/PH)) group. Behaviors were assessed using the adhesive removal test, rotarod test and social interaction test at 1st, 7th, 14th and 21st days after stroke. Serum biochemical analysis was also performed on the behavioral testing days. Results showed THAT serum corticosterone and MDA levels in CO/PH group were significantly lower than CO/SI group. Serum BDNF levels in CO/PH group was significantly higher than CO/SI group. Serum corticosterone and MDA levels in ST/PH group were lower than ST/SI group. In ST/PH group, serum Total antioxidant capacity (TAC) and BDNF levels were significantly higher than ST/SI group. Biochemical analysis of certain regions of the brain (hippocampus, striatum and cerebral cortex) was performed on 21st day after stroke. In the hippocampus of CO/PH group, BDNF and TAC levels were significantly higher than CO/SI group. The hippocampal MDA level of CO/PH group were significantly lower than CO/SI group. BDNF and TAC levels in the hippocampus, striatum and cerebral cortex of ST/PH group were significantly higher and MDA level was significantly lower as compared with ST/SI group. Both ischemic groups showed sensorimotor recovery over a 21-day period, but recovery of ST/PH group was significantly greater than ST/SI group. Total social interaction time in ST/PH group was significantly longer than ST/SI group. Based on the results of this study, social interaction after stroke enhances histologic and sensorimotor recovery through reduction of HPA activity and corticosterone release, leading to increased TAC and BDNF levels.

Curcumin mitigates stress induced depression and hippocampal damage through upregulation of BDNF expression and adult neurogenesis.

Chronic stress, recognized as a major precipitant of depression, has been linked to various neural alterations, including cell death, neuronal atrophy, and compromised hippocampal neurogenesis and plasticity. This study aim to scrutinize curcumin's influence on glucocorticoid hormone secretion and its subsequent effects on the structural integrity and neurogenesis of the hippocampal neurons. A total of 30 adult albino Wistar rats, each weighing between 200-250 g, were utilized for the study. The rats, excluding those in the control group, underwent a 42-day regimen of modified Chronic Unpredictable Stress (CUS) to induce depressive-like states. After inducing CUS, these rats were categorized into six groups, each receiving different oral treatments for two weeks. The treatments included 30 mg/kg body weight of curcumin, 20 mg/kg body weight of fluoxetine, or a combination of both, along with a control group that received distilled water and an olive oil treated group. The rats were tested for behavioural despair using the forced swim test and their blood samples were obtained for serum corticosterone test. Afterwards, the rats were anesthetized, transcardially perfused and the hippocampus dissected and prepared for histopathological study. The study's multi-faceted approach encompassed behavioral, biochemical, and histological evaluations. Behavioral despair, gauged through the forced swimming test, displayed a marked reduction in the curcumin-treated rats compared to controls (p&lt;0.05). Additionally, curcumin significantly lowered serum corticosterone levels, aligning them closely with the control levels. Histomorphological analysis of the hippocampus showed that the curcumin- treated rats exhibited substantially less neurodegeneration, as evidenced by fewer cytoplasmic vacuolations and more intact neuronal structures. Increased cell proliferation and BDNF level were also observed in curcumin treated rats. This study has illuminated a multifaceted approach through which curcumin mitigates hippocampal neurodegeneration, thus showing possible therapeutic potential of curcumin in ameliorating depressive symptoms.

Time-dependent dual mode of action of COX-2 inhibition on mouse serum corticosterone levels

To elucidate the effect of cyclooxygenase-2 (COX-2) inhibition on corticosterone release, mice were divided into a group receiving NS398, a selective COX-2 inhibitor at a dose of 3 mg/kg for seven days, and a group receiving NS398 for fourteen days. After this time, the mice were sacrificed, and blood serum was collected. An ELISA protocol was used to analyze serum corticosterone levels. Short-term COX-2 inhibition increased corticosterone levels, while long-term inhibition lowered them. The exact schedule of experiments was repeated after the lipopolysaccharide (LPS) Escherichia coli challenge in mice to check the influence of stress stimuli on the tested parameters. In this case, we observed increases in corticosterone levels, significant in a seven-day pattern. These results indicate that corticosterone levels are regulated through a COX-2-dependent mechanism in mice.