Magnetic resonance spectroscopy of hippocampal and striatal neurometabolites in experimental PTSD rat modeling

The spectrum of the metabolites in the dorsal region of the hippocampus and striatum was studied using the method of 1H magnetic resonance spectroscopy at experimental modeling of the posttraumatic stress disorder syndrome (PTSD) in rats. PTSD was reproduced by exposure of the cat cue to rats daily along 10 day by 10 minutes at once. The anxiety level of animals was estimated 12 days later after the end of the experimental series of stress. Based on the anxiety index, the rats were divided into 3 phenotypes. The animals with an anxiety index > 0.8 (group 1) had lower plasma corticosterone compared with rats form the control group. In animals with an anxiety index in the range 0.7–0.8 (group 2), an elevated corticosterone level was noted. The rats with an anxiety index < 0.7 (group 3) had a lower plasma corticosterone level compared with animals from the control group. Rats of group 2 were characterized by an increased level of GABA in the hippocampus compared with controls. In the remaining groups, the percentages of GABA in the hippocampus and striatum did not differ significantly from the control. The distribution of NAA differed form that of GABA. The highest level of NAA was found in the striatum for rats from group 1, whereas NAA in animals form groups 1 or 3 did not differ from the control. The NAA level in the hippocampus was similar between all groups, including the control. The results obtained indicate that multiple exposures to psychological stress associated with the sense of proximity of a natural enemy in some animals cause an anxiolytic reaction. These animals are characterized by a stable corticosterone level and a stable level of neurometabolites in the studied structures of the brain. For rats with the highest level of anxiety, a lowered level of corticosterone with a constant level of neurometabolites in the hippocampus and striatum is characteristic. And only in rats with an intermediate level of anxiety, synchronization was observed between the increase in plasma corticosterone and the increase in hippocampal GABA content. The results obtained are in good agreement with the ideas of the protective action of glucocorticoids under PTSD manifested in  restraining violations of the psycho-physiological status. The mate rials allow the neurobiological mechanisms of the protective action of glucocorticoids to be detailed

Anxiety and neurometabolite levels in the hippocampus and amygdala after prolonged exposure to predator-scent stress

Here, to study the relationship between anxiety levels with changes in the neurometabolic profile in the hippocampus and amygdala, an experimental predator stress model was reproduced in which Sprague-Dawley rats were exposed to cat urine for 10 minutes on a daily basis for 10 days. At the time of presentation of the stimulus, an online survey of behavioral reactions was conducted. Fear, aggressiveness, avoidance of stimulus and grooming were recorded. Fourteen days after the completion of the last stress exposure, the total level of anxiety was determined in the test of the“cross maze”. Using the method of in vivo NMR spectroscopy, the content of neurometabolites was determined in the hippocampus and in the amygdala. According to the peculiarities of behavioral reactions to a stressor, animals were retrospectively divided into two phenotypes. The first phenotype used a passive behavioral strategy, and the second phenotype was active. In animals of the first phenotype, the indicators of anxiety behavior remained at the control level. In animals of the second phenotype, a decrease in anxiety was observed. Animals of the second phenotype showed elevated levels of lactate in the hippocampus compared to animals of the first phenotype, and the lowest N-acetylaspartate levels significantly differed from those in the control and the first phenotype animals. In the amygdala, in animals of the second phenotype, the content of taurine is sharply reduced in comparison with those in the control and the animals of the first phenotype. Thus, the results obtained indicate a relationship of post-stress changes in anxiety, with the peculiarities of the behavioral reactions presented at the moment of the immediate action of the stressor. Among the hippocampal and amygdala neurometabolites, the most informative for the characterization of the anxiolytic action of the predator stress are identified

The effect of repeated episodes of immobilization stress on resistance to combined effects of exercise and low temperature, the level of corticosterone and the relationship between prooxidant and antioxidant enzymes in the blood of rats with different resistance to hypoxia

In animals with intermediate resistance to hypoxia, there was initially a higher level of corticosterone than in intact animals and in animals with both high resistance and low resistance to hypoxia. Animals with intermediate resistance to hypoxia were characterized by greater endurance during swimming at a low temperature.У животных обладающих промежуточной устойчивостью к гипоксии был исходно более высокий уровень кортикостерона, чем у интактных животных и у животных как с высокой устойчивостью, так и с низкой устойчивостью к гипоксии. Животные с промежуточной устойчивостью к гипоксии характеризовались большей выносливостью во время плаванья при низкой температуре

Limited Cheese Intake Paradigm Replaces Patterns of Behavioral Disorders in Experimental PTSD: Focus on Resveratrol Supplementation

Currently, the efficacy of drug therapy for post-traumatic stress disorder or PTSD leaves much to be desired, making nutraceutical support a promising avenue for treatment. Recent research has identified the protective effects of resveratrol in PTSD. Here, we tested the behavioral and neurobiological effects of combining cheese consumption with resveratrol supplements in an experimental PTSD model. Using the elevated plus maze test, we observed that cheese intake resulted in a shift from anxiety-like behavior to depressive behavior, evident in increased freezing acts. However, no significant changes in the anxiety index value were observed. Interestingly, supplementation with cheese and resveratrol only led to the elimination of freezing behavior in half of the PTSD rats. We further segregated the rats into two groups based on freezing behavior: Freezing+ and Freezing0 phenotypes. Resveratrol ameliorated the abnormalities in Monoamine Oxidize -A and Brain-Derived Neurotrophic Factor gene expression in the hippocampus, but only in the Freezing0 rats. Moreover, a negative correlation was found between the number of freezing acts and the levels of Monoamine Oxidize-A and Brain-Derived Neurotrophic Factor mRNAs in the hippocampus. The study results show promise for resveratrol supplementation in PTSD treatment. Further research is warranted to better understand the underlying mechanisms and optimize the potential benefits of resveratrol supplementation for PTSD. © 2023 by the authors.23-15-20040; Russian Science Foundation, RSFThis work was supported by the Russian Scientific Foundation, Regional grant, Chelyabinsk Region (#23-15-20040)

Offensive behavior, striatal glutamate metabolites, and limbic–hypothalamic–pituitary–adrenal responses to stress in chronic anxiety

Variations in anxiety-related behavior are associated with individual allostatic set-points in chronically stressed rats. Actively offensive rats with the externalizing indicators of sniffling and climbing the stimulus and material tearing during 10 days of predator scent stress had reduced plasma corticosterone, increased striatal glutamate metabolites, and increased adrenal 11-dehydrocorticosterone content compared to passively defensive rats with the internalizing indicators of freezing and grooming, as well as to controls without any behavioral changes. These findings suggest that rats that display active offensive activity in response to stress develop anxiety associated with decreased allostatic set-points and increased resistance to stress. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.The Russian Science Foundation (grant № 17-15-013418) supported this study. This was supported in part by the contracts of the Ministry of Education and Science of the Russian Federation with South Ural State University (17.7255.2017/8.9) and Institute of Immunology and Physiology (AAAA-A18-118020690020-1). The work was furthermore supported by institutional funds from the State University of New York (SUNY) Upstate Medical University. This work is part of the TransCampus project between TU Dresden and King’s College London and was partially supported by the U.S. Department of Veterans Affairs (5101CX001219) and the U.S. Department of Defense (W81XWH-16-1-0773)

Big Five Traits as Predictors of a Healthy Lifestyle during the COVID-19 Pandemic: Results of a Russian Cross-Sectional Study

The healthy lifestyle of people around the world has changed dramatically during the COVID-19 pandemic. The personality risk factors for these processes from around the world remain understudied. This study aimed to examine the associations of the Big Five traits with a healthy lifestyle during the COVID-19 pandemic. In a cross-sectional study, data from 1215 Russian university students were analyzed. Participants completed the Big Five Inventory-10 and Short Multidimensional Inventory Lifestyle Evaluation. The results showed that personality traits predicted many dimensions of a healthy lifestyle during the COVID-19 pandemic. Diet and nutrition were positively predicted by extraversion, agreeableness, and conscientiousness, and it was negatively predicted by neuroticism. Substance abuse was positively predicted by agreeableness and conscientiousness, and it was negatively predicted by extraversion. Physical activity was positively predicted by extraversion and conscientiousness, and it was negatively predicted by neuroticism. Stress management was positively predicted by extraversion and conscientiousness, and it was negatively predicted by neuroticism. Restorative sleep was positively predicted by extraversion and conscientiousness, and it was negatively predicted by neuroticism. Social support for healthy practices was positively predicted by extraversion, agreeableness, and conscientiousness. Environmental exposures were positively predicted by extraversion, and neuroticism was positively and negatively predicted by conscientiousness. Our findings may be useful for further exploration of personality risk factors for healthy practices in challenging life circumstances. © 2022 by the authors.AAAA-A21-121012090090-9; Russian Foundation for Basic Research, РФФИ: 20-515-55003This study was funded by RFBR (project No. 20-515-55003) and partly by the Government contract of the Institute of Immunology and Physiology (AAAA-A21-121012090090-9)

Does stress-induced release of interleukin-1 cause liver injury?

It is well established that repeated immobilization stress (RIS) is induced by increased levels of cytokines and the emergence of lesions in the liver. Our data prove that interleukin-1 (IL-1) causes liver lesions in stressed Wistar rats. In essence, the relationship between IL-1 and stress-induced liver injury is based on three findings: (1) IL-1b treatment causes liver inflammation, consisting of infiltrating monocytes and the appearance of necrosis by increasing lipid peroxidation and protein carbonylation. Positive correlations between the content of heptane-soluble diene conjugates and an area of necrosis, as well as between content carbonylated proteins and an area of necrosis, were found after injection of IL-1b to unstressed rats. (2) RIS is accompanied by increased levels of circulating IL-1b and corticosterone. In the liver, stress causes the emergence of foci of necrosis with perivascular and lobular infiltration of mononuclear cells as well as increased free radical oxidation. Moreover, there were observed down-regulations of cytochrome P450 (CYP)- dependent enzymes, CYP1A1 activities, and decreased CYP1A1 mRNA content. Positive correlations between the level of circulating IL-1b and necrosis areas, as well as between circulating IL-1b and the content of heptanesoluble diene conjugates, were observed in stressed rats. In addition, the positive correlation between necrosis foci and heptane-soluble diene conjugates was revealed after stress cessation. (3) Use of the IL-1 receptor antagonist Anakinra at a dose of 2 lg/kg to treat the effects of stress prevents infiltration of mononuclear cells and reduces the level of free radical oxidation as well as necrosis of lesions. As a result, blocking IL-1 receptors with an antagonist significantly rescues stress-induced liver injury, suggesting that IL-1 might be involve in the cascade of liver injury that initiated by sustained stress. © Springer Science+Business Media, LLC 2012

The Link between Activities of Hepatic 11beta-Hydroxysteroid Dehydrogenase-1 and Monoamine Oxidase-A in the Brain Following Repeated Predator Stress: Focus on Heightened Anxiety

We investigated the presence of a molecular pathway from hepatic 11-βHSD-1 to brain MAO-A in the dynamics of plasma corticosterone involvement in anxiety development. During 14 days following repeated exposure of rats to predator scent stress for 10 days, the following variables were measured: hepatic 11-βHSD-1 and brain MAO-A activities, brain norepinephrine, plasma corticosterone concentrations, and anxiety, as reflected by performance on an elevated plus maze. Anxiety briefly decreased and then increased after stress exposure. This behavioral response correlated inversely with plasma corticosterone and with brain MAO-A activity. A mathematical model described the dynamics of the biochemical variables and predicted the factor(s) responsible for the development and dynamics of anxiety. In the model, hepatic 11-βHSD-1 was considered a key factor in defining the dynamics of plasma corticosterone. In turn, plasma corticosterone and oxidation of brain ketodienes and conjugated trienes determined the dynamics of brain MAO-A activity, and MAO-A activity determined the dynamics of brain norepinephrine. Finally, plasma corticosterone was modeled as the determinant of anxiety. Solution of the model equations demonstrated that plasma corticosterone is mainly determined by the activity of hepatic 11-βHSD-1 and, most importantly, that corticosterone plays a critical role in the dynamics of anxiety following repeated stress. © 2022 by the authors. Licensee MDPI, Basel, Switzerland