Serum Corticosterone Levels Research Articles

Myostatin and Related Factors Are Involved in Skeletal Muscle Protein Breakdown in Growing Broilers Exposed to Constant Heat Stress.

Simple SummaryOur results showed that constant heat stress could affect the expression of myostatin and related factors involved in skeletal muscle protein breakdown in growing broilers, resulting in a decrease in muscle protein deposition. These findings suggest a new strategy for regulating muscle protein breakdown in growing broilers, which could benefit the modern broiler industry in combating constant heat stress.Heat stress has an adverse effect on the development of poultry farming, which has always aroused great concern. This study was carried out to investigate the protein breakdown mechanism responsible for the suppressive effect of constant heat stress on muscle growth in growing broilers. A total of 96, 29-day-old, Arbor Acres male broilers were randomly divided into two groups, a thermoneutral control (21 ± 1 °C, TC) and a heat stress (31 ± 1 °C, HS) group, with six replicates in each group and eight birds in each replicate. The trial period lasted for 14 d, and the trial was performed at 60 ± 7% relative humidity, a wind speed of <0.5 m/s and an ammonia level of <5 ppm. The results showed that the average daily feed intake and average daily gain in the HS group were distinctly lower than those in the TC group (p < 0.05), whereas the HS group showed a significantly increased feed conversion ratio, nitrogen excretion per weight gain and nitrogen excretion per feed intake compared to the TC group (p < 0.05). In addition, the HS group showed a significantly reduced breast muscle yield and nitrogen utilization in the broilers (p < 0.05). The HS group showed an increase in the serum corticosterone level (p < 0.05) and a decrease in the thyroxine levels in the broiler chickens (p < 0.05) compared to the TC group, whereas the HS group showed no significant changes in the serum 3,5,3′-triiodothyronine levels compared to the TC group (p > 0.05). Moreover, the HS group showed increased mRNA expression levels of myostatin, Smad3, forkhead box O 4, muscle atrophy F-box and muscle ring-finger 1, but reduced mRNA expression levels of the mammalian target of rapamycin, the protein kinase B and the myogenic determination factor 1 (p < 0.05). In conclusion, the poor growth performance of birds under constant heat stress may be due to an increased protein breakdown via an mRNA expression of myostatin and related factors.

Probiotics alleviate depressive behavior in chronic unpredictable mild stress rat models by remodeling intestinal flora.

To explore the effects of probiotics on depressive behavior in a chronic unpredictable mild stress (CUMS) rat model by remodeling intestinal flora. Twenty-four male SD rats aged 6-8 weeks were randomly divided into four groups: control group, depression group (CUMS), depression+paroxetine group (Paro) and depression+probiotics group (Pro). Sucrose preference, open field and forced swimming tests were used to assess depression-like behavior in rats. ELISA was used to detect the levels of adrenocorticotropic hormone (ACTH), and corticosterone, norepinephrine and 5-hydroxytryptamine in rat serum. Real-time PCR was used to determine the changes of Lactobacillus, Bifidobacterium, Enterococcus faecalis and Escherichia coli in rat cecum. Compared with the control group, CUMS led to significant decreases of body weight, total traveled distance, duration in central area, immobility time, norepinephrine and 5-hydroxytryptamine contents in hippocampal tissues, as well as Lactobacillus and Bifidobacterium in the cecum. It also resulted in marked increases of the contents of E. faecalis and E. coli in the cecum, ACTH and corticosterone contents in the serum of rats. Paroxetine and probiotic treatment each diminished or prevented these changes. By remodeling intestinal flora, probiotics can reduce the CUMS-induced depressive behavior of rats, increase the levels of norepinephrine and 5-hydroxytryptamine, and inhibit the expression of ACTH and corticosterone. Significantly, the effect of both paroxetine and probiotic on microorganisms is similar.

Human Adrenal Cortical Zone Changes With Aging

Background: Previous adrenal morphological studies have shown that the zona reticularis (ZR) and the zona glomerulosa (ZG) decrease in size with aging. Although several lines of evidence indicate that the hypothalamic-pituitary-adrenal axis becomes hyperactive in elderly, little is known about age-related transformations of the adrenal zona fasciculata (ZF). Objectives: To investigate the morphological and functional changes of the adrenal cortex across the adult life span, with emphasis on: 1) the understudied ZF, and 2) potential sexual dimorphisms. Methods: We used immunohistochemistry to evaluate the expression of several cortical proteins: aldosterone synthase (CYP11B2), visinin-like protein 1 (VSNL1), 3β-hydroxysteroid dehydrogenase type II (HSD3B2), 11β-hydroxylase (CYP11B1) and cytochrome b5 type A (CYB5A). The ZF area was estimated by subtracting the VSNL1-positive (a ZG marker) area from the HSD3B2-expressing area (ZG and ZF). All captured images were quantitated by ImageJ. In addition, we employed liquid chromatography-tandem mass spectrometry to quantify the morning serum concentrations of 6 steroids: cortisol, 11-deoxycortisol (11dF), 17α-hydroxyprogesterone (17OHP4), 11-deoxycorticosterone (DOC), corticosterone, and androstenedione (A4). The Mann-Whitney U test and Spearman’s rank correlation coefficients were used for statistical analysis, as appropriate. Results: We included 60 adrenal glands from 30 men and 30 women, with ages between 18–86 years. The total cortical area was positively correlated with age (r=0.34, p=0.008), and this association was significant only in men (p=0.02). Both the total (VSNL1-positive) and functional ZG (CYP11B2-positive) areas declined abruptly with aging in men (r=-0.57 and -0.76, p=0.001 and p<0.0001, respectively), but not women (p=0.06 and 0.27, respectively). The CYB5A-positive area, marking the ZR, correlated negatively with age (r=-0.76, p<0.0001) in both sexes. In contrast, the estimated ZF area showed a strong positive correlation with age both in men (r=0.59, p=0.0006) and women (r=0.49, p=0.007), while CYP11B1-positive area remained stable across ages (p=0.86). Finally, we measured morning levels of 6 steroids in 149 men and 149 women, with ages between 21–95 years, matched for age and body mass index. Serum cortisol, corticosterone, and DOC levels remained relatively stable across ages (p=0.38, 0.64 and 0.25, respectively), while 11dF levels increased slightly with age (r=0.16 and p=0.007), particularly so in men (p=0.005). Expectedly, 17OHP4 and A4 declined with aging (r=-0.37 and -0.37, p<0.0001 for both). Conclusions: In contrast with the ZG and ZR, the ZF and the total adrenal cortex area enlarge with aging. An abrupt decline of the ZG occurs with age in men, but not in women, possibly contributing to sexual dimorphism in cardiovascular risk.

Regulatory effect of curcumin on splenic inflammation in overtraining rats and its mechanism

Objective: To study the alleviating effects of curcumin on splenic inflammation in overtraining rats by regulating toll-like receptor 4 (TLR4)-p38 mitogen-activated protein kinase (p38 MAPK)/nuclear factor-kappa B (NF-κB) signaling pathway. Methods: Male Wistar rats of 7-week old were divided into control group (C group, 12), overtraining model group (OM group, 11), curcumin + overtraining model group (COM group, 14). C Group did not undergo any exercise intervention. OM and COM group underwent 8-week incremental load swimming training. During the training, rats in the COM group were treated with 200 mg/ (kg·d) curcumin in the volume as 5 ml/kg, and the other groups were treated with an equal volume of 0.5 % sodium carboxymethylcellulose. 24 hours after the last training, the spleen index was calculated by weighing, the pathological changes of the spleen were observed by light microscopy, and the biochemical indicators of blood and spleen were detected. Results: After 8-week incremental load swimming training, the splenic structure in C group was normal under light microscope; the spleen index of OM group was significantly lower than that of C group (P＜0.01) and pathological changes of inflammation were obvious; the spleen index of COM group was significantly higher than that of OM group (P＜0.05) and pathological changes of inflammation were alleviated. Compared with C group, in OM group, the serum levels of corticosterone (Cor), NF-κB, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and TLR4 expression rate on splenic monocytes surface, splenic TNF-α, IL-6 were increased (P＜0.05 or P＜0.01), the expressions of p38 MAPK, phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) and NF-κB in spleen were increased (P＜0.05 or P＜ 0.01); serum testosterone (T), serum and splenic interleukin-10 (IL-10) were decreased (P＜0.01). Compared with OM group, in COM group, serum levels of Cor, NF-κB, TNF-α, IL-6 and TLR4 expression rate on splenic monocytes surface, splenic TNF-α, IL-6 were decreased (P＜0.05 or P＜0.01), the expressions of p38 MAPK, p-p38 MAPK and NF-κB in spleen were decreased (P＜ 0.05); serum T, serum and splenic IL-10 were increased (P＜0.05). The trend of T/Cor ratio between groups was consistent with testosterone change. Conclusion: The 8-week incremental load swimming training aggravated inflammation of spleen in rats, led to pathological inflammatory changes. Curcumin supplementation during training can down-regulate expressions of TLR4-p38 MAPK/NF-κB signaling pathway-related proteins, thereby maintaining a dynamic equilibrium between pro-inflammatory/anti-inflammatory cytokines, protecting the spleen.

Selective Inhibition of 11β-Hydroxysteroid Dehydrogenase Type 1 Attenuates High-Fat Diet-Induced Hepatic Steatosis in Mice.

IntroductionThe effect of 11β-hydroxysteroid dehydrogenase type1 (11β-HSD1) inhibition on hepatic steatosis is incompletely understood. Here, we aimed to determine the therapeutic effect of BVT.2733, a selective 11β-HSD1 inhibitor, on hepatic steatosis.Materials and MethodsC57B/6J mice were randomly divided into a low-fat diet (LFD) fed group and a high-fat diet (HFD) fed group. Mice were fed with HFD for 28 weeks which induced obesity and severe hepatic steatosis. The two groups were further divided into four groups as follows: LFD, LFD with BVT.2733, HFD, and HFD with BVT.2733. Mice in LFD+BVT and HFD+BVT groups were intraperitoneally injected with BVT.2733 daily for 30 days. Effects of BVT.2733 on mice body weight, serum lipid profile, serum free fatty acids (FFAs), glucocorticoid levels, gene expression in adipose and liver tissues were assessed.ResultsInjection of a low dose of BVT.2733 (50 mg/kg/day) reduced body weight and hyperlipidemia, but did not improve glucose tolerance and insulin resistance in diet-induced obese mice. The low dose of BVT.2733 attenuated hepatic steatosis, liver injury, and liver lipolytic gene expression in diet-induced obese mice. Besides, the low dose of BVT.2733 reduced fat mass and lipolysis in visceral adipose tissues, hepatic FFAs, and serum corticosterone levels in diet-induced obese mice.ConclusionOur study shows that moderate inhibition of 11β-HSD1 by BVT.2733 reduces FFAs and corticosterone synthesis in fatty tissues, thereby attenuates the delivery of corticosterone and FFAs to the liver. Collectively, this prevents high-fat diet-induced hepatic steatosis.

Stress Controllability Modulates Basal Activity of Dopamine Neurons in the Substantia Nigra Compacta.

Prolonged stress induces neural maladaptations in the mesolimbic dopamine (DA) system and produces emotional and behavioral disorders. However, the effects of stress on activity of DA neurons are diverse and complex that hinge on the type, duration, intensity, and controllability of stressors. Here, controlling the duration, intensity, and type of the stressors to be identical, we observed the effects of stressor controllability on the activity of substantia nigra pars compacta (SNc) DA neurons in mice. We found that both lack and loss of control (LOC) over shock enhance the basal activity and intrinsic excitability of SNc DA neurons via modulation of Ih current, but not via corticosterone serum level. Moreover, LOC over shock produces more significant enhancement in the basal activity of SNc DA neurons than that produced by shock per se, and therefore attenuates the response to natural reward. This attenuation can be reversed by control over shock. These results indicate that although chronic stress per se tends to enhance the basal activity of SNc DA neurons, LOC over the stressor is able to induce a larger enhancement in the basal activity of SNc DA neurons and produce more severe behavioral deficits. However, control over stress ameliorates the deleterious effects of stress, highlighting the role of stress controllability.

The Cerebellum under Stress: Dietary African Walnut (Tetracarpidium conophorum)Abrogates Oxidative Stress-driven Neuropathology induced by Chronic Unpredictable Stress

Background: Consumption of a healthy diet abundant in antioxidant and anti-inflammatory phytochemicals, offers an effective and least expensive way to prevent neurodegeneration. Herein, the role of Tetracarpidium conophorum (African walnut) enriched diet in chronic stress-induced cerebellar neuropathology was investigated Methodology: Twenty-one male Wistar rats were used for this investigation. Rats were randomly assigned into three groups (A, B, and C), each consisting of 7 rats (n = 7). Group A (Control group) were fed control diet; group B rats were subjected to different chronic unpredictable stressors (CUS) + control diet for 21 days, while group C rats were subjected to CUS + Walnut-enriched diet for 21 days. Serum corticosterone levels, the expression level of antioxidant and inflammatory markers, and cytoarchitectural changes in cerebellum were assessed by enzyme-linked immunosorbent assay (ELISA) immunohistochemistry methods. Results: The walnut-enriched diet prevented astrogliosis, modulated serum corticosterone expression, and tumor necrotic factor-α in the cerebellum. The walnut-enriched diet also caused an improvement in the antioxidant profile, indicating that it suppressed chronic unpredictable stress-induced perturbations. Conclusion: Our results suggest that African walnut exerts protective effects against oxidative stress-driven dysfunction by reducing serum corticosterone levels, modulating oxidative stress pathways, and preventing neuronal morphological damage in the cerebellum.

Neonatal maternal separation increases the number of p27-positive Sertoli cells in prepuberty

Neonatal maternal separation (NMS) is an experimental model for early life stress, which affects the growth and development of various organs, resulting in adverse health effects in humans and animals. In our previous study, we demonstrated that NMS [(0.5-, 1-, 2-h/day NMS, from postnatal day (PND) 1–10] induced morphological changes to the male reproductive system, including decreased Sertoli cell numbers in mouse testes at PND 70. To clarify the mechanism by which NMS decreases Sertoli cell numbers, we evaluated the effects of NMS on mouse testes at PNDs 10 and 16. At PND 10, the Sertoli cell number was not significantly different among experimental groups; however, it decreased in 0.5- and 2-h/day NMS mice at PND 16. The termination of Sertoli cell proliferation in prepuberty can be induced by p27, a cyclin-dependent kinase inhibitor. At PND 10, we observed an increase in the number of p27-positive Sertoli cells in 2-h/day NMS mice. The seminiferous tubule diameters decreased significantly in 1- and 2-h/day NMS mice, and the relative interstitial area increased in 2-h/day NMS mice. Serum corticosterone level significantly increased, and serum testosterone level significantly decreased in the 2-h/day NMS mice. At PND 16, the tubule diameters and height of seminiferous epithelium were significantly higher in 0.5- and 2-h/day NMS mice. Our results suggest that NMS disturbs serum corticosterone and testosterone levels and increases the number of p27-positive Sertoli cells at PND 10, resulting in a decrease in the number of Sertoli cells at PND 16.

Simulated vehicle exhaust exposure induces sex-dependent behavioral deficits in rats

Chronic exposure to vehicle exhaust emissions are known to cause several adverse health effects. In this study, we examined the impact of several parameters of behavioral, cardiovascular and biochemical functions upon exposure of pro-oxidants CO2, NO2 and CO (simulated vehicle exhaust exposure: SVEE) in male and female rats. Adult rats were subjected to SVEE or ambient air in whole body chambers (5 h/day, 2 weeks). Male, but not female, rats developed memory deficits, and exhibited anxiety- and depression-like behavior, accompanied with significantly high levels of serum corticosterone, oxidative stress, and inflammatory markers (CRP and TNFα), associated with lower levels of total antioxidant capacity, glutathione, glyoxalase and superoxide dismutase (SOD) activities. Brain region-specific downregulation of Cu/Zn SOD, Mn SOD, GSR, PKCα, ERK1/2, CaMKIV, CREB, BDNF and NMDAR subunit protein expression were also observed in male, but not female, rats. Blood pressure, heart rate and eGFR were not negatively impacted by SVEE. Our results suggest that SVEE, through its pro-oxidant content, induces oxido-inflammation in susceptible brain regions in a sex-dependent manner.

Investigating the basis for the antidepressant effects of Gleditsiae spina using an integrated metabolomic strategy.

Objective(s): Gleditsiae spina (GS) is a natural antidepressant but its mechanisms of action remain unclear. In the present study, taxifolin (Tax) was selected to determine the role of flavonoids in the antidepressant effects of GS.Materials and Methods:Urine samples from C57BL/6 mice were analyzed based on ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q/TOF-MS). Then, we investigated the therapeutic effects of GS and Tax in depression models in vivo. An integrated metabolomic approach was used to examine the metabolic profiles of GS/Tax groups and corticosterone model groups (Cor). Metabolic networks in response to GS/Tax treatment were established for the comparison of antidepressant activities.Results:Corticosterone exposure significantly increased serum levels of corticosterone but decreased serum levels of 5-hydroxytryptamine and sucrose consumption (P<0.01). Treatment with GS and Tax improved all measured variables compared to those of the corticosterone-exposed group (P< 0.01). The antidepressant effects of GS and Tax involved the regulation of pentose and glucuronate interconversions, arginine and proline metabolism, phenylalanine metabolism, taurine and hypotaurine metabolism, and the citrate cycle.Conclusion:These findings indicate that flavonoids form the pharmacodynamic basis of the antidepressant effects of GS. Moreover, our findings highlight that integrated metabolomics provides a powerful tool to study the mechanisms and material basis of Chinese herbs.

Effect of Nucleus Basalis Magnocellularis Lesions on Memory and Hippocampal Brain-Derived Neurotrophic Factor, IL-1β, Glucose, and Corticosterone Levels in Adult Rats

Background: The nucleus basalis magnocellularis (NBM) sends projections to the hippocampus that are implicated in learning and memory formation. Despite ample evidence proposing that cognitive function impairment related to neurodegeneration, it may result from alteration of biochemical substances. We aimed to investigate the effects of NBM lesions on the hippocampal interleukin-1beta (IL-1β), brain-derived neurotrophic factor (BDNF), and corticosterone levels, as inflammation markers, and hallmarks of neurodegeneration, stress, and metabolic status. Methods: Thirty-six male Wistar rats were randomly put in control, sham, and NBM-lesioned groups. After inducing the lesion using an intra-NBM injection of 10 μg ibotenic acid (5 μg/μL, each side) in rats, memory was estimated using the passive avoidance test. Moreover, serum and hippocampal IL-1β levels, as well as the hippocampal corticosterone, BDNF, and glucose levels were measured after 42 days. Results: Findings indicated a significant impairment of retention at different intervals in the NBM-lesioned group. BDNF decreased whereas corticosterone, glucose, and IL-1β levels increased in the hippocampus. Also, the levels of serum IL-1β, hippocampal BDNF, corticosterone, and glucose had significant correlations with hippocampal IL-1β levels. Conclusion: The synchronous alterations of some hippocampal factors, including BDNF, corticosterone, IL-1β, and glucose, caused by NBM lesion suggest that their interaction might play a significant role in neurodegeneration and relevant learning and memory impairments.

Sleep disturbance induces depressive behaviors and neuroinflammation by altering the circadian oscillations of clock genes in rats

Sleep loss leads to a spectrum of mood disorders such as anxiety disorders, bipolar disorder and depression in many individuals. However, the underlying mechanisms are largely unknown. In this study, sleep-disturbed animals were tested for anxiety and depressive behaviors. We then studied the effects of SD on hypothalamic-pituitary-adrenal (HPA) axis function by measuring serum and CSF levels of corticosterone (CORT), and at the end of the experiment, brains were collected to measure the circadian oscillations of clock genes expression in the hypothalamus, glial cell activation and inflammatory cytokine alterations. Our results indicated that SD for 3 days resulted in anxiety- and depressive-like behaviors. SD exaggerated cortisol response to HPA axis, significantly altered the circadian oscillations of clock genes, decreased the expression of tight junction protein ZO-1 and Claudin 5 and increased the number of GFAP-positive cells and Iba-1-positive cells and caused subsequent elevation of pro-inflammatory cytokines IL-6, IL-1β and TNFα. These findings demonstrated that SD for 3 days induced anxiety- and depression-like behaviors in rats in company with altering the circadian oscillations of clock genes and inducing neuroinflammation, indicating the underlying mechanism of sleep loss induced neuronal dysfunction.

Chronic Inhibition of FAAH Reduces Depressive-Like Behavior and Improves Dentate Gyrus Proliferation after Chronic Unpredictable Stress Exposure

Symptoms of depressive disorders such as anhedonia and despair can be a product of an aberrant adaptation to stress conditions. Chronic unpredictable stress model (CUS) can generate an increase in the activity of the hypothalamic-pituitary-adrenal axis (HPA) and induce a reduction of neurotrophin signaling and the proliferation of neural progenitors in the adult dentate gyrus, together with increased oxidative stress. Levels of the endocannabinoid anandamide (AEA) seem to affect these depression-by-stress-related features and could be modulated by fatty acid amide hydrolase (FAAH). We aimed to evaluate the effects of FAAH inhibitor, URB597, on depressive-like behavior and neural proliferation of mice subjected to a model of CUS. URB597 was administered intraperitoneally at a dose of 0.2 mg/kg for 14 days after CUS. Depressive-like behaviors, anhedonia, and despair were evaluated in the splash and forced swimming tests, respectively. Alterations at the HPA axis level were analyzed using the relative weight of adrenal glands and serum corticosterone levels. Oxidative stress and brain-derived neurotrophic factor (BDNF) were also evaluated. Fluorescence immunohistochemistry tests were performed for the immunoreactivity of BrdU and Sox2 colabeling for comparison of neural precursors. The administration of URB597 was able to reverse the depressive-like behavior generated in mice after the model. Likewise, other physiological responses associated with CUS were reduced in the treated group, among them, increase in the relative weight of the adrenal glands, increased oxidative stress, and decreased BDNF and number of neural precursors. Most of these auspicious responses to enzyme inhibitor administration were blocked by employing a cannabinoid receptor antagonist. In conclusion, the chronic inhibition of FAAH generated an antidepressant effect, promoting neural progenitor proliferation and BDNF expression, while reducing adrenal gland weight and oxidative stress in mice under the CUS model.

Systemic Effects of Occlusal Disharmony on Corticosterone Serum Levels in Rattus Norvegicus

Background: Mastication process occurs over time and it can lead to occlusal reduction of the teeth. Thiscauses reducing occlusal contact of teeth and it will lead to disharmony occlusion disorders. The occlusiondisharmony is recognized by the body as a stressor that systemically affects the homeostasis in the body,especially the production of hormones.Objective: The aim of this study was to determine the systemic effect of occlusal disharmony on corticosteroneserum levels in Rattus norvegicus.Method: The research method of this study used experimental design and conducted among 7 male RattusNorvegicus in each groups. In intervention group, an occlusal reduction was ± 1 mm in all molars andfor control group did not given any intervention. Moreover, at 1st day, 7th day, 14th day and 21st day wastaken 2 cc of blood via infraorbital vein. The measurement of Corticosterone levels used Enzyme LinkedImmunosorbent Assay (ELISA).Result: Anova test results showed that corticosterone levels was significant difference between each groups(p &lt;0.05). Tukey HSD test showed there was a significant difference between intervention group and controlgroup on 1st day, in intervention group on 7th day (p &lt;0.05).Conclusion. The results of this study showed that there were differences of corticosterone serum levelsamong mice who experienced occlusion disharmony so it concluded that the dental occlusion disharmonyhad a systemic impact to corticosterone serum levels in Rattus norvegicus

The role of pre-pubertal training history on hippocampal neurotrophic factors and glucocorticoid receptor protein levels in adult male rats

Neurotrophic factors play an integral role in hippocampal plasticity, and interaction with HPA axis components, especially glucocorticoid receptors (GR), can mediate the structural and functional changes. In the present work, we investigated the long-term effects of combined exercise training (CET) and voluntary physical activity in an enriched environment (EE) in the pre-pubertal period on hippocampal neurotrophic factors and GR. For this purpose, a longitudinal study was designed. After three weeks, all rats were kept in the standard cages without any interventions until adulthood. Western blot analysis revealed a significant increase in hippocampal BDNF and VEGF protein levels in both EE and CET groups (P < 0.001), along with an increase in GR protein levels. In addition, EE decreased serum corticosterone levels compared to CET (P < 0.05). Serum insulin-like growth factor-1 (IGF-1) levels did not demonstrate remarkable changes between groups. Training interventions during sensitive developmental periods may produce profound and long-lasting effects on the hippocampus, at least in part by interactive effects of neurotrophic factors cascades and GR.

High-salt diet suppresses autoimmune demyelination by regulating the blood–brain barrier permeability

Sodium chloride, "salt," is an essential component of daily food and vitally contributes to the body's homeostasis. However, excessive salt intake has often been held responsible for numerous health risks associated with the cardiovascular system and kidney. Recent reports linked a high-salt diet (HSD) to the exacerbation of artificially induced central nervous system (CNS) autoimmune pathology through changes in microbiota and enhanced TH17 cell differentiation [M. Kleinewietfeld et al., Nature 496, 518-522 (2013); C. Wu et al., Nature 496, 513-517 (2013); N. Wilck et al., Nature 551, 585-589 (2017)]. However, there is no evidence that dietary salt promotes or worsens a spontaneous autoimmune disease. Here we show that HSD suppresses autoimmune disease development in a mouse model of spontaneous CNS autoimmunity. We found that HSD consumption increased the circulating serum levels of the glucocorticoid hormone corticosterone. Corticosterone enhanced the expression of tight junction molecules on the brain endothelial cells and promoted the tightening of the blood-brain barrier (BBB) thereby controlling the entry of inflammatory T cells into the CNS. Our results demonstrate the multifaceted and potentially beneficial effects of moderately increased salt consumption in CNS autoimmunity.

Multigenerational nicotine exposure affects offspring nicotine metabolism, nicotine-induced hypothermia, and basal corticosterone in a sex-dependent manner

Parental nicotine exposure can impact phenotypes in unexposed offspring. Our laboratory recently published data showing that nicotine reward and hippocampal gene expression involved in stress pathways were perturbed in F1 offspring of male C57BL/6J mice chronically exposed to nicotine. For the current study, we aimed to further test nicotine and stress-sensitivity phenotypes that may predict vulnerability to nicotine addiction in new cohorts of F1 offspring derived from nicotine-exposed males. We tested locomotor and body temperature sensitivity to acute nicotine administration, serum concentration of nicotine and nicotine metabolites after acute nicotine dosing, and serum corticosterone levels in male and female F1 offspring of nicotine- or saline-exposed males. Paternal nicotine exposure reduced sensitivity to nicotine-induced hypothermia in males, altered nicotine metabolite concentrations in males and females, and reduced serum basal corticosterone levels in females. These findings may point to reduced susceptibility to nicotine addiction-related phenotypes as a result of parental nicotine exposure.

Cellular mechanisms of impaired mineralocorticoid and glucocorticoid production by endocrine disruptor DDT

Developmental exposure to persistent endocrine disruptors is of a great concern. Affection of adrenal hormones production by low-dose exposure to dichlorodiphenyltrichloroethane (DDT) has been revealed recently. Objective of the research – investigation of ultrastructural mechanisms of impaired mineralocorticoid and glucocorticoid production after prenatal and postnatal exposure to endocrine disruptor DDT. Male Wistar rats exposed to low doses of DDT during prenatal and postnatal development were studied. Aldosterone and corticosterone levels in serum were measured by enzyme-linked immunosorbent assay, histological examination and electron microscopy of the adrenals were performed. Pubertal rats, developmentally exposed to low doses of DDT, demonstrated lowered aldosterone and elevated corticosterone serum levels. After puberty the rats showed tendency to normalization of hormones’ production. Morphological examination of the adrenals revealed less developed zona glomerulosa in pubertal period and its relative hyperplasia after puberty. Microcirculatory disorders and focal cell death were observed in outer zona fasciculata. Electron microscopy of glomerulosa cells found signs of suppressed secretory activity in pubertal period and no significant reduction of mitochondria size in adult rats. Total number of mitochondria in 1 µm2 of cytoplasm and percent of mitochondria with swollen matrix were diminished compared to the control. Cells of inner zona fasciculata demonstrated increased functional activity. Age-dependent changes in fine structure of fasciculata cells were similar to the control, but were more pronounced. In this way, cellular mechanism of impaired mineralocorticoid production in rats prenatally and postnatally exposed to low doses of endocrine disruptor DDT, are insufficient mitochondrion function and impaired reorganization of mitochondrial apparatus, which occurs during pubertal period. Mechanisms of elevated glucocorticoid secretion are attributed to enhanced function of mitochondria in fasciculata cells.

Relationship between locomotor activity rhythm and corticosterone levels during HCC development, progression, and treatment in a mouse model.

Cancer-related fatigue (CRF) and stress are common symptoms in cancer patients and represent early side effects of cancer treatment which affect the life quality of the patients. CRF may partly depend on disruption of the circadian rhythm. Locomotor activity and corticosterone rhythms are two important circadian outputs which can be used to analyze possible effects on the circadian function during cancer development and treatment. The present study analyzes the relationship between locomotor activity rhythm, corticosterone levels, hepatocellular carcinoma (HCC) development, and radiotherapy treatment in a mouse model. HCC was induced in mice by single injection of diethylnitrosamine (DEN) and chronic treatment of phenobarbital in drinking water. Another group received chronic phenobarbital treatment only. Tumor bearing animals were divided randomly into four groups irradiated at four different Zeitgeber time points. Spontaneous locomotor activity was recorded continuously; serum corticosterone levels and p-ERK immunoreaction in the suprachiasmatic nucleus (SCN) were investigated. Phenobarbital treated mice showed damped corticosterone levels and a less stable 24hours activity rhythm as well as an increase in activity during the light phase, reminiscent of sleep disruption. The tumor mice showed an increase in corticosterone level during the inactive phase and decreased activity during the dark phase, reminiscent of CRF. After irradiation, corticosterone levels were further increased and locomotor activity rhythms were disrupted. Lowest corticosterone levels were observed after irradiation during the early light phase; thus, this time might be the best to apply radiotherapy in order to minimize side effects.

A nutty idea: Exploring a novel method using a hazelnut cocoa spread to temporarily increase maternal care behavior within a rat litter.

Maternal care plays a crucial role for infant development. In humans, skin-to-skin care is often used for preterm infants to reduce acute stress and improve long-term developmental outcome. Here we propose a new translational approach to study the effects of acute increases in maternal care on offspring development in rodents. First, pilot studies determined that dams spent more time licking pups covered in hazelnut cocoa spread (Nutella® )) than any other studied substance. For the main experiment, Sprague-Dawley rats were bred in-house, and Nutella® was applied four times a day to treatment pups (2 males/females per litter) of seven litters from PN2 to 5. Control pups (2 males/females per litter) were handled similarly without applying any substance. Maternal licking and grooming behavior was observed for 30min following each Nutella® application. Nutella® -covered pups received significantly more licking and grooming compared to control pups within each litter. There was no difference in body weight or basal serum corticosterone levels between Nutella® -covered and control pups on PN5, suggesting that the Nutella® application and subsequent increased maternal licking was not stressful for the pups. Future studies will investigate whether this increase in maternal care can protect pups from stress- or pain-induced rises in corticosterone.