Serum Corticosterone Concentrations Research Articles

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.

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

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

Performance, slaughter traits and serum corticosterone levels in COBB500 broiler chickens fed lycopene-supplemented diets during heat period

Poultry farmers in the tropics suffer great losses in broiler production especially during the post brooding phase as a result of heat stress occasioned by high ambient temperature. This study therefore, investigated the ameliorative effects of synthetic lycopene dietary supplement on growth performance, slaughter traits and serum corticosterone (CORT) levels of COBB500 broiler chickens reared during heat period. A total of 120 birds were selected at 4th week of rearing and allotted into a control group (C) and three experimental groups designated as T1, T2 and T3. Each group had 3 replicates. The four groups were fed the same starter diet for 4 weeks and then differently on finisher diet supplemented with lycopene at 0mg/kg feed (control), 5mg/kg (T1), 10mg/kg (T2), and 15mg/kg (T3) for 3 weeks. Data obtained were analyzed for statistical differences using ANOVA. The results showed that lycopene supplementation increased feed intake significantly (p<0.05) in the birds under groups T1 and T3. Final body weights and weight gain were statistically similar across the groups but numerically improved in the lycopene-supplemented broilers. While the thigh muscle weight increased significantly (p<0.05) across the groups with increasing supplementation, feed conversion ratio (FCR) decreased optimally (2.03) at 15mg/kg supplementation level leading to improved general performance. The supplement also decreased serum CORT concentration significantly (p<0.05) at 5mg/kg level. Therefore, lycopene can be supplemented in diets at 5mg/kg feed as an anti-stress and performance enhancer in COBB500 broiler chickens reared under hot climate.

Impact of chronic psychological stress on platelet membrane fatty acid composition in a rat model of type 1 diabetes Mellitus

BackgroundChronic stress and diabetes mellitus are highly associated with oxidative stress and inflammation, resulting in cell membrane disruption and platelet activity. This study aims to evaluate the impact of chronic psychological stress on the composition of the platelet phospholipid membrane and platelet activation in type 1 diabetes mellitus (T1DM).MethodsWe enrolled 35 mature healthy female Wistar rats and randomly divided them into 4 groups, namely the control group (n = 9), stress group (n = 10), T1DM group (n = 8), and T1DM + Stress group (n = 8). The Wistar rats were treated in different experimental conditions for 28 days while being provided free access to feed and water. The concentration of corticosterone in blood serum and hair samples was measured using a competitive enzyme-linked immunosorbent assay. Gas chromatography-mass spectrometry was conducted to identify the methyl esters of fatty acids (FAs) in the platelet phospholipid membrane. A quantitative determination of 11-dehydro-thromboxane B2 in the blood serum was also performed using a competitive enzyme-linked immunosorbent assay.ResultsAfter 28 days, the concentration of corticosterone in blood serum (ng/mL) was observed to be higher in the stress group as compared to the T1DM and T1DM + Stress groups (P = 0.031 and P = 0.008, respectively). The percentage of C 16:0 FA in the platelet membrane was greater in the T1DM + Stress group, but its levels of C 20:1 omega (ω) 9 FA, including C 18:3ω3 FA, C 20:5ω3 FA, and the total sum of ω3 FAs, were lower as compared to the control group (P = 0.016; P = 0.016; P = 0.031; P = 0.016, P = 0.031). The concentration of 11-dehydro-thromboxane B2 in blood serum (pg/mL) was observed to be higher in the stress group than in rats with T1DM (P = 0.063).ConclusionChronic psychological stress is related to higher levels of corticosterone, saturated FAs acids in the platelet membrane, and greater platelet activation. This study proves how a low percentage of unsaturated fatty acids in the DM and stress groups indicates the disturbing impact of the oxidative/inflammatory environment to lipid metabolism and neuroendocrine response.

Coated sodium butyrate and vitamin D3 supplementation improve gut health through influencing intestinal immunity, barrier, and microflora in early-stage broilers.

Intestinal development and function are critical to maintaining sustained broiler growth. The present study aimed to evaluate the effects of coated sodium butyrate (CSB) and vitamin D3 (VD3) on the intestinal immunity, barrier, oxidative stress and microflora in early-stage broilers. In total, 192 one-day-old broilers were assigned to a 2 × 2 factorial design including two dietary supplements at two different levels, in which the main effects were VD3 (3000 or 5000 IU kg-1) and CSB (0 or 1 g kg-1). The results showed that CSB supplementation increased ileal goblet cells (GCs) numbers, villus height and decreased crypt depth in broilers. CSB increased ileal proliferating cell nuclear antigen expression and high-level VD3 decreased cluster of differentiation 3 expression. CSB reduced serum d-lactate, endotoxin (ET), adrenocorticotropic hormone, corticosterone and malondialdehyde (MDA) concentrations and increased total antioxidant capacity (T-AOC) level. Meanwhile, high-level VD3 decreased serum ET concentration. Furthermore, CSB increased ileal T-AOC, lysozyme (LYZ) and transforming growth factor (TGF)-β and decreased MDA, whereas high-level VD3 decreased ileal MDA and increased secretory immunoglobulin A. CSB up-regulated ileal claudin1, superoxide dismutase 1, TGF-β and LYZ mRNA expression and down-regulated interleukin-1β mRNA expression. CSB combined with high-level VD3 increased ileal Faecalibaculum abundance. Spearman correlation analysis showed that Faecalibaculum was related to the immune and barrier function. Dietary supplementation with CSB and high-level VD3 improved early gut health in broilers by promoting intestinal development, enhancing antioxidant capacity, strengthening barrier function and enhancing the favorable composition of the gut bacterial flora. © 2024 Society of Chemical Industry.

Research Note: Non-invasive urate sphere corticosterone metabolite as a novel biomarker for heat stress in poultry

Heat stress (HS) poses a critical concern for the global poultry industry. To better understand its impact and mechanism on poultry species, as well as to develop effective HS mitigation options, it is crucial to validate reliable and effective biomarkers of HS. In this study, broiler chickens (96 mixed-sex, 1-day-old) were randomly assigned to 2 environmental conditions: HS at 31°C for 8 h/d versus a thermoneutral condition (TN) at 24°C ± 0.2 throughout the day, from d 21 to d 28. After 7 d of cyclic HS, blood serum samples and the urate sphere (the white portion of the chicken excreta) were collected to measure specific HS biomarkers, including corticosterone, heat shock protein 70 (HSP70), Triiodothyronine (T3), and urate sphere corticosterone metabolite. The results showed that the concentrations of HSP70, T3, and serum corticosterone were not significantly different (P > 0.05) between the heat-stressed and thermoneutral birds in this study. However, heat-stressed birds recorded higher (P < 0.01) concentration (pg/mL) of urate corticosterone metabolite compared to TN birds. Data presented here thus provide preliminary evidence suggesting the use of non-invasive urate sphere corticosterone metabolite as a heat stress biomarker in poultry.

Changes in the Metabolism of Fucose-Containing Biopolymers in Rat Gastrointestinal Tissues under Immobilization Stress

The features of fucoglycoprotein metabolism in blood serum and tissues of gastrointestinal tract of rats in the dynamics of experimental stress on 21, 35, 60, 90 days of observation were considered. In blood serum and in homogenates of liver, stomach and small intestine of immobilized rats multidirectional changes in the level of fucose and fucosidase activity were observed. They are manifested by a decrease in the amount of total fucose in blood serum and liver of rats against the background of low activity of the enzyme degrading fucoglycoproteins. The same changes were detected in the tissues of the gastric and small intestine (except on day 35 of the experiment, when the growth of fucose and fucosidase was visualized), which may indicate a change in metabolism toward anabolism. These changes correlate with an increase in the concentration of corticosterone in the blood serum of the rats.

Exploring the effects of noise pollution on physiology and ptilochronology of birds.

An ex-situ study was carried out to determine the impact of noise on physiology and ptilochronology of non-breeding male domesticated quail birds. During 60-days long trial, male quail birds, aged 5-weeks, weighing (c.100gm) were used. Out of 72 experimental birds, 18 birds were assigned to the Control Group (G1) while remaining 54 birds were divided equally into 3 treatment groups: Road Traffic noise (G2), Military activity noise (G3) and Human Activities noise (G4). Birds were housed in standard-sized separate cages (20 ×45 × 20 cm), every bird was kept apart in separate cage in open laboratory under maintained environmental conditions. Millet seeds and water were provided to all the experimental birds ad libitum. Noise originated from several sources of recorded high-intensity music (1125 Hz/ 90 dB), was administered for 5-6 hours per day. Observations were recorded in the morning and afternoon. The experiment was conducted during the non-breeding season from August to October in triplicate. Blood sampling was done after 60 days. According to the current study, noise stress significantly (p<0.05) increased the concentrations of creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, uric acid, cholesterol, triglycerides, total protein, and glucose while a decline in the levels of albumin was seen in treatment birds of G3. While in terms of hematology, total white blood cells count (TWBC), total red blood cells count (TRBC), mean cell volume (MCV) & packed cell volume (PCV) concentrations were raised in blood of treatment birds of G3. In terms of hormones, noise stress significantly (p<0.05) increased the serum concentrations of Corticosterone in G3 while a significant (p<0.05) decline was observed in the concentrations of luteinizing hormone (LH), thyroid stimulating hormone (TSH), and follicle stimulating hormone (FSH) in the same group. Moreover, fault bar formation in G3 was more prominent than others. Noise stress can significantly affect serology, hematology, hormonal physiology and ptilochronology in quail birds.

Impact of early posthatch feeding on the immune system and selected hematological, biochemical, and hormonal parameters in broiler chickens

Under commercial conditions, chicks hatch within a 24 to 48 h window, a period known as the hatching window. Subsequently, they undergo various treatments before finally being transported to the broiler farm. These procedures may delay the chicks' access to food and water, sometimes receiving them as late as 72 h after hatching. Previous studies have indicated that fasting during this initial period is detrimental, leading to impaired body growth, compromised immune system response, and hindered muscle development. The objective of this study was to assess the impact of early posthatch feeding on immune system organs and selected hematological, biochemical, and hormonal parameters. The experiment utilized Ross 308 broiler eggs incubated under typical commercial hatchery conditions. The experimental group's eggs were hatched in HatchCare hatchers (HC) with immediate access to feed and water, while the control group's eggs were hatched under standard conditions (ST). Thirty chickens from each group were assessed on the 1st (D1), 7th (D7), 21st (D21), and 35th (D35) day after hatching. On D1, the HC group exhibited lower hemoglobin, hematocrit, and total serum protein values, suggesting that early access to water prevents initial dehydration in newborn chicks. Conversely, the ST group showed a stress reaction on D1 due to feed deprivation, leading to an almost 2-fold higher serum corticosterone concentration compared to the HC group. However, this increase did not result in a significant change in the heterophil/lymphocyte ratio. Furthermore, the HC group displayed an increase in triglyceride concentration and a decrease in HDL concentration on D1. On D7, the HC group exhibited an increased relative weight of the bursa and a higher CD4+ cell number in the cecal tonsil (CT), indicating a more rapid development of these organs resulting from early stimulation of the gastrointestinal tract. However, early feeding did not influence the numbers of Bu-1+, CD4+, and CD8+ cells or the germinal center (GC) areas in the spleen. In conclusion, early feeding contributes to the welfare of newborn chicks by reducing dehydration and stress levels and stimulating the development of gut-associated lymphoid tissue.

Molecular Mechanisms of the Regulation of Liver Cytochrome P450 by Brain NMDA Receptors and via the Neuroendocrine Pathway—A Significance for New Psychotropic Therapies

Recent investigations have highlighted the potential utility of the selective antagonist of the NMDA receptor GluN2B subunit for addressing major depressive disorders. Our previous study showed that the systemic administration of the antagonist of the GluN2B subunit of the NMDA receptor, the compound CP-101,606, affected liver cytochrome P450 expression and activity. To discern between the central and peripheral mechanisms of enzyme regulation, our current study aimed to explore whether the intracerebral administration of CP-101,606 could impact cytochrome P450. The injection of CP-101,606 to brain lateral ventricles (6, 15, or 30 µg/brain) exerted dose-dependent effects on liver cytochrome P450 enzymes and hypothalamic or pituitary hormones. The lowest dose led to an increase in the activity, protein, and mRNA level of CYP2C11 compared to the control. The activities of CYP2A, CYP2B, CYP2C11, CYP2C6, CYP2D, and protein levels of CYP2B, CYP2C11 were enhanced compared to the highest dose. Moreover, CP-101,606 increased the CYP1A protein level coupled with elevated CYP1A1 and CYP1A2 mRNA levels, but not activity. The antagonist decreased the pituitary somatostatin level and increased the serum growth hormone concentration after the lowest dose, while independently decreasing the serum corticosterone concentration of the dose. The findings presented here unveil a novel physiological regulatory mechanism whereby the brain glutamatergic system, via the NMDA receptor, influences liver cytochrome P450. This regulatory process appears to involve the endocrine system. These results may have practical applications in predicting alterations in cytochrome P450 activity and endogenous metabolism, and potential metabolic drug–drug interactions elicited by drugs that cross the blood–brain barrier and affect NMDA receptors.

Impact of mechanical vs. manual catching on stress, fear, and carcass quality in slower growing broilers

ABSTRACT This study evaluated manual and mechanical catching methods on slower growing broiler chickens on the day of processing. Ten catching events, five mechanical and five manual, were evaluated for animal welfare and an additional set of 241 catches, 128 manual and 113 machine, were analyzed to determine the effect on carcass quality. No significant difference in serum corticosterone concentration (CORT) was found between the catching methods (p = 0.9). Pre-catching CORT (15.07 ± 2.24) was significantly lower than post-catching (25.41 ± 2.22) (p < 0.001). Manually caught broilers had four times greater odds of tonic immobility (TI) than mechanically caught birds (OR 4.0, 95% CI: 1.54–10.54) (p < 0.001). Birds also had 77% lower odds of TI before being caught than after, irrespective of catching method. Manually caught birds had 19% greater risk of bruised wings (p < 0.05) and 23% greater risk of bruised legs (p < 0.05). Lower odds of TI and decreased risk of injury in the machine caught birds indicate improved welfare and carcass quality compared with manual catching. Overall, machine catching was found to improve welfare and carcass quality in these slower growing broilers.

Saffron carotenoids reversed the UCMS-induced depression and anxiety in rats: Behavioral and biochemical parameters, and hippocampal BDNF/ERK/CREB and NR2B signaling markers

BackgroundDepression is a debilitating condition that affects the mind and the individual's body. The improving effects of saffron on depression and anxiety have long been discussed, with limited information about the molecular mechanism of action. Hypothesis/PurposeInvestigating the effect of saffron carotenoids, Crocin and Crocetin, on depression and anxiety in rats by emphasizing some signaling pathways involved. Study DesignDepression and anxiety were induced in rats via unpredictable chronic mild stress (UCMS). Then different rat groups were treated with Crocin, Crocetin, Fluoxetine, and vehicle. Behavioral tests were done before and after treatment. MethodsThe serum Serotonin and Corticosterone and the expression of some hippocampal signaling proteins were studied. Furthermore, bioinformatics tools were used to predict the interactions of Crocin/ Crocetin with the Serotonin transporter and NMDA receptor subunit NR2B. Then, the patch-clamp was used to study the interaction of Crocetin with the NMDA receptor. ResultsVarious behavioral tests confirmed the induction of depression and the improvement of depression by these natural carotenoids. In addition, Crocin/ Crocetin significantly increased the decreased serum Serotonin and reduced the increased serum Corticosterone in the depressed groups. They also increased or caused a trend of increase in the CREB, ERK, BAD, BDNF, p11, and 5-HT1B expression in the hippocampus of the depressed groups. In addition, there were an increase or a trend in p-CREB/CREB, p-ERK1/2 /ERK1/2, and p-BAD/BAD ratios in the Crocin/ Crocetin treated depressed groups. However, the NR2B and FOXO3a expression showed a trend of decrease in depressed groups after treatment. The bioinformatics data indicated that Crocin/ Crocetin could bind to the Serotonin transporter (SLC6A4) and NR2B subunit of the NMDA receptor. Both carotenoids bind to the same site as Fluoxetine in the SLC6A4. However, they bound to different sites on the NR2B. So, Crocetin binds to NR2B at the same site as Ifenprodil. But Crocin bound to another site. The whole cell patch-clamp recording on the normal rat hippocampus revealed a significant decrease in the NMDA peak amplitude after Crocetin treatment, indicating its inhibitory effect on this receptor. ConclusionThe antidepressant activities of Crocin/ Crocetin are possibly due to their effects on Serotonin and Corticosterone serum concentrations, NR2B expression, and the downstream signaling pathways. Furthermore, these natural carotenoids, like Fluoxetine, induced an increasing tendency in p11 and 5HT1B in depressed rats.

A prolonged stress rat model recapitulates some PTSD-like changes in sleep and neuronal connectivity

Chronic post-traumatic stress disorder (PTSD) exhibits psychological abnormalities during fear memory processing in rodent models. To simulate long-term impaired fear extinction in PTSD patients, we constructed a seven-day model with multiple prolonged stress (MPS) by modifying manipulation repetitions, intensity, and unpredictability of stressors. Behavioral and neural changes following MPS conveyed longitudinal PTSD-like effects in rats for 6 weeks. Extended fear memory was estimated through fear retrieval induced-freezing behavior and increased long-term serum corticosterone concentrations after MPS manipulation. Additionally, memory retrieval and behavioral anxiety tasks continued enhancing theta oscillation activity in the prefrontal cortex-basal lateral amygdala-ventral hippocampus pathway for an extended period. Moreover, MPS and remote fear retrieval stimuli disrupted sleep-wake activities to consolidate fear memory. Our prolonged fear memory, neuronal connectivity, anxiety, and sleep alteration results demonstrated integrated chronic PTSD symptoms in an MPS-induced rodent model.

Effect of zolmitriptan on blood pressure-relevant cardiovascular biomarkers in rats with experimentally induced hypertension

Background and objective: Zolmitriptan is among widely used medicines for the management of migraine attach, zolmitriptan is acting through stimulating serotonin (5-HT1B/1D) receptors that will cause cranial vasoconstriction. This study was aimed to compare and evaluate the impact of zolmitriptan on the relevant cardiovascular and renal biomarkers during hypertension in rats with experimentally induced hypertension. Methods: Twenty-four Wister albino male rats were randomly divided into four groups of six rats each. The first group (Group I) of rats served as the control group. To induce hypertension, the rats in the second (Group II), third (Group III) and fourth (Group IV) groups have received an intraperitoneal injection of cadmium chloride CdCl2 a dose of 1.5 mg/kg/day for 14 days. The rats in Group II were considered as the positive control. Whereas, rats in Group III received zolmitriptan orally (2 mg/kg/day), and Group IV rats received nifedipine dose of 10mg/kg for two weeks concurrently with CdCl2. Results: Inducing hypertension with CdCl2 injection significantly increased the systolic, diastolic, and mean blood pressure in Group II compared with Group I, respectively. The systolic, diastolic, and mean blood pressure in rats that received zolmitriptan did not exhibit any statistically significant differences from the rats in Group II, whereas nifedipine has significantly reduced blood pressure in group IV rats. Intraperitoneal injection of CdCl2 increased the concentrations of endothelin and nitric oxide as well as renin activity level in hypertensive Group II rats compared to control rats. Zolmitriptan administration did not produce any significant change in the endothelin and nitric oxide levels. Inducing hypertension in rats significantly reduced the corticosterone level. In contrast, administering medications in Group III and VI rats did not produce any statistically significant change in the serum concentration of corticosterone. Conclusion: Zolmitriptan administration (2 mg/kg/day, p.o) showed no statistically significant effects on the systolic, diastolic, and mean blood pressure in rats with experimentally induced hypertension. Zolmitriptan has also failed to produce any statistically significant change in the levels of endothelin-1, renin, nitric oxide, corticosterone, and serum creatinine in rats with hypertension.

Maternal preconceptional inflammation transgenerationally alters metabolic and behavioral phenotypes in offspring

AimsEvidence is accumulating that maternal inflammation induces phenotypic changes in the next generation. However, whether maternal preconceptional inflammation alters metabolic and behavioral phenotypes in offspring remains poorly understood. Main methodsFemale mice were injected with either lipopolysaccharide or saline to establish the inflammatory model and then allowed to mate with normal males. Offspring from both control and inflammatory dams were subsequently given chow diet and water ad libitum, without any challenge, for metabolic and behavioral tests. Key findingsMale offspring derived from inflammatory mothers (Inf-F1) maintained on the chow diet developed impaired glucose tolerance and hepatic ectopic fat deposition. Hepatic transcriptome sequencing showed the largest gene changes related to the metabolic pathway. Moreover, Inf-F1 mice exhibited anxiety- and depressive-like behaviors and were accompanied by higher serum corticosterone concentration and lower glucocorticoid receptor abundance in the hippocampus. SignificanceThe results expand the current knowledge of developmental programming of health and disease to include maternal preconceptional health and provide a basis for understanding metabolic and behavioral alterations in offspring linked to maternal inflammation.

Fatty acid amide hydrolase inhibitor URB597 suppressed conditioned and sensitized fear responses in a rat model of post-traumatic stress disorder

BackgroundPost-traumatic stress disorder (PTSD) is a debilitating disorder that results from exposure to various traumatic events. Endocannabinoids levels change during PTSD. Inhibition of fatty acid amide hydrolase (FAAH), the enzyme responsible for anandamide degradation, has shown potential in treating PTSD. MethodsWe used male Wistar rats and single prolonged stress plus shock as the experimental model of PTSD-like phenotype. Freezing times during conditioned fear response (CFR) and sensitized fear response (SFR) were recorded. The effect of URB597 (0.1, 0.3, and 0.6 mg/kg), a FAAH inhibitor, and fluoxetine (10 mg/kg) as control drug on CFR and SFR were evaluated for two weeks. After the test, the anxiety-like and depression-like behaviors of the animals were assessed by elevated plus-maze and forced swim test, respectively. The serum concentration of corticosterone was also measured at the end of the experiments. ResultsThe results showed that fluoxetine and URB597 suppressed freezing time in both CFR and SFR procedures. The drugs showed apparent anxiolytic-like and antidepressant-like effects. URB597 at the dose of 0.6 mg/kg decreased corticosterone level. ConclusionsThe results of the present study showed that URB597 induced a protective effect against experimental PTSD-like phenotype. Regarding its anxiolytic-like and antidepressant-like effects, the drug may be suggested as a potential treatment for PTSD.

Состояние функций нервной системы крыс Вистар при применении пептида тафтцин-ПГП (селанк) в условиях иммобилизационного стресса

The aim of the study was to investigate the state of functions of the nervous system of Wistar rats upon application of the peptide taftsin-PGP under conditions of chronic stress. Materials and methods. The experiments were performed on 45 male Wistar rats weighing 200-230 g. Selank peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) was injected intraperitoneally at doses of 80, 250 and 750 μg/kg 15 min before stressor exposure. Animals were divided into 5 groups (n = 9): 1 - control (non-stressed animals injected with saline); 2 - stress (stressed animals injected with saline); 3-5 - stress+taftsin-PGP at doses of 80, 250 and 750 µg/kg. Animals were stressed for 28 days; from days 15 to 28, they were injected with selank/saline. The neurotropic effects of selank were evaluated in the elevated plus-maze, open field (OF) and forced swimming tests. To assess the severity of stress response, the concentration of corticosterone in rat serum was evaluated using enzyme immunoassay. Results. It was found that 28-day immobilisation stress caused disturbances of nervous system functions in the form of increased anxiety, horizontal, vertical, locomotor activity, emotionality and expression of depressive behaviour, as well as increased concentration of corticosterone in blood serum of experimental animals. Taftsin-PGP administration against the background of preliminary stressing (from the 15th to the 28th day of the experiment) contributed to a decrease in the severity of stress-induced behavioural changes in rats: at a dose of 750 µg/kg the peptide had anxiolytic effect, 250 µg/kg - antidepressant effect. At the same time, these changes occurred against the background of a significant decrease in serum corticosterone level. Conclusion. Thus, selank corrects stress-induced changes in the state of nervous system functions under 28-day restraint stress.

The Impact of Social Isolation and Environmental Deprivation on Blood Pressure and Depression-Like Behavior in Young Male and Female Mice

Background: Social isolation (SI) and loneliness are major adult and adolescent health concerns, particularly in the coronavirus disease 2019 (COVID-19) era. Recent prospective cohort studies indicate that older women who experienced both SI and loneliness had a significantly higher risk of cardiovascular disease (CVD). Hypertension, a well-established risk factor for CVD, is more prevalent in elderly women than men. Furthermore, a lack of social relationships is strongly associated with an increased risk of hypertension in middle-aged and elderly women compared to men. Although this has not been extensively studied, adolescents and young adults who experience loneliness or SI may also be at risk for CVD and depression. The purpose of this study was to examine the effect of SI on blood pressure and depression-like behavior in young male and female mice. Methods: Weaned C57BL/6 mice were randomly assigned (n = 6/group/sex) to either group housing (GH) or SI. Animals in the SI group were housed in individual cages for 8 weeks with no view of other animals. The cages were kept in ventilated racks to prevent pheromone exposure and socially isolated animals had no cage enrichment. Results: SI increased systolic, diastolic, and mean arterial blood pressure in females and elevated heart rate in both sexes. Body weight gain was dramatically increased in socially isolated females but tended to decrease in socially isolated males. In the forced swim test, which detects depression-like behavior, there was no difference between groups in total immobility time. The latency to immobility, however, was significantly decreased in socially isolated females. Serum concentrations of corticosterone and metanephrine did not differ between socially isolated and group-housed females, but corticosterone levels were significantly reduced in socially isolated males. Conclusions: Our results indicate that 8 weeks of SI leads to significant changes in blood pressure and heart rate and mild changes in depression-like behavior in young mice, with females affected more than males.

The effect of occlusal disharmony on a chronic stress-induced animal model of gut microbiota dysbiosis.

Chronic stress (CS) is closely related to intestinal health. Occlusal disharmony (OD) is a risk factor for hypersensitivity to novel stress, and the relationship between OD and the intestinal system with or without other chronic stresses remains unclear. Therefore, the purpose of this study was to investigate whether OD affects the gut microbiota and the intestinal barrier in a CS-exposed animal model. OD was induced by making a 0.5-mm-thick incision on the right maxillary molar. CS involved exposure to one stressor per day for 35 days. Sprague-Dawley rats were randomly divided into an untreated control group and OD-, CS- and OD + CS-treated groups. The behavioural tests, serum corticosterone level, gut microbiota composition and tight junction protein expression in colon tissue were measured on the 56th day to elucidate the effect of OD on animals under CS. Significant differences in performance on behavioural tests and serum corticosterone concentrations were observed on day 56 in the OD + CS group compared with the control group. Exposure to occlusal disharmony or chronic stress resulted in a change in the composition of the gut microbiota of rats. Differences in the expression of the tight junction proteins zonula occludens-1 and junctional adhesion molecule-A were observed in colon tissue from the OD + CS group compared with the control group. We concluded that the significant changes in performance on behavioural tests, serum corticosterone concentrations and microbiota dysbiosis and tight junction protein levels induced by OD with CS may indicate that OD is a potential factor promoting gut microbiota dysbiosis.

Serum concentrations of corticosterone and sex hormones and their relationship in farmed Morelet’s crocodile (Crocodylus moreletii)

Background: Crocodile farming aims to produce high-quality skins from captive crocodilians. Captivity usually exposes the animals to stressful conditions, resulting in increased serum corticosterone (CORT) levels that correlate negatively with those of sex hormones and reproductive success. Objective: To evaluate serum concentrations of CORT and sex hormones and their relationship in farmed Morelet’s crocodiles (Crocodylus moreletii) during the non-breeding (NBS) and breeding (BS) seasons. Methods: The study included 59 adult crocodiles (29 females and 30 males). One blood sample was collected in NBS (n=31) and BS (n=28) from each crocodile to determine serum concentrations of CORT, estradiol (E2), progesterone (P4), and testosterone (T). Crocodiles were kept in mixed-sex groups and were fed once or twice a week throughout the study. Results: In females, CORT was higher in NBS (p&lt;0.05) but had no correlation with E2 or P4 in any season (p&gt;0.05). In males, CORT was similar in NBS and BS (p&gt;0.05) and had no correlation with T (p&gt;0.5). Conclusion: The CORT levels had no effect on sex hormones. This could be explained by low CORT levels resulting from farming conditions where the animals were not exposed to severe or chronic stress.