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.

Unveiling the Link: Exploring Mitochondrial Dysfunction as a Probable Mechanism of Hepatic Damage in Post-Traumatic Stress Syndrome.

PTSD is associated with disturbed hepatic morphology and metabolism. Neuronal mitochondrial dysfunction is considered a subcellular determinant of PTSD, but a link between hepatic mitochondrial dysfunction and hepatic damage in PTSD has not been demonstrated. Thus, the effects of experimental PTSD on the livers of high anxiety (HA) and low anxiety (LA) rats were compared, and mitochondrial determinants underlying the difference in their hepatic damage were investigated. Rats were exposed to predator stress for 10 days. Then, 14 days post-stress, the rats were evaluated with an elevated plus maze and assigned to HA and LA groups according to their anxiety index. Experimental PTSD caused dystrophic changes in hepatocytes of HA rats and hepatocellular damage evident by increased plasma ALT and AST activities. Mitochondrial dysfunction was evident as a predominance of small-size mitochondria in HA rats, which was positively correlated with anxiety index, activities of plasma transaminases, hepatic lipids, and negatively correlated with hepatic glycogen. In contrast, LA rats had a predominance of medium-sized mitochondria. Thus, we show links between mitochondrial dysfunction, hepatic damage, and heightened anxiety in PTSD rats. These results will provide a foundation for future research on the role of hepatic dysfunction in PTSD pathogenesis.

Resistance to Resveratrol Treatment in Experimental PTSD Is Associated with Abnormalities in Hepatic Metabolism of Glucocorticoids.

Glucocorticoids are metabolized by the CYP3A isoform of cytochrome P450 and by 11-ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD-1). Experimental data suggest that post-traumatic stress disorder (PTSD) is associated with an increase in hepatic 11ß-HSD-1 activity and a concomitant decrease in hepatic CYP3A activity. Trans-resveratrol, a natural polyphenol, has been extensively studied for its antipsychiatric properties. Recently, protective effects of trans-resveratrol were found in relation to PTSD. Treatment of PTSD rats with trans-resveratrol allowed the rats to be divided into two phenotypes. The first phenotype is treatment-sensitive rats (TSR), and the second phenotype is treatment-resistant rats (TRRs). In TSR rats, trans-resveratrol ameliorated anxiety-like behavior and reversed plasma corticosterone concentration abnormalities. In contrast, in TRR rats, trans-resveratrol aggravated anxiety-like behavior and decreased plasma corticosterone concentration. In TSR rats, hepatic 11ß-HSD-1 activity was suppressed, with a concomitant increase in CYP3A activity. In TRR rats, the activities of both enzymes were suppressed. Thus, the resistance of PTSD rats to trans-resveratrol treatment is associated with abnormalities in hepatic metabolism of glucocorticoids. The free energy of binding of resveratrol, cortisol, and corticosterone to the human CYP3A protein was determined using the molecular mechanics Poisson-Boltzmann surface area approach, indicating that resveratrol could affect CYP3A activity.

Can Resveratrol Influence the Activity of 11ß-Hydroxysteroid Dehydrogenase Type 1? A Combined In Silico and In Vivo Study.

The enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD-1) is an NADPH-dependent reductase, responsible for the activation of cortisol by reducing cortisone. Resveratrol (RES), a type of natural polyphenol, is reported to be able to slow the progression of cancer and cardiovascular disease and improve the health of mice on a high-calorie diet. In this article, we applied molecular docking and molecular dynamics simulations to investigate the possibility of binding RES to 11ß-HSD-1. The 11ß-HSD-1:RES complex is stable on the µs time scale, and backbone RMSD-based clustering identified three conformations. Special attention was paid to the interaction pattern between the ligand and the target molecule, revealing hydrogen bonds between the hydroxyl group of RES and Thr124, as well as hydrophobic interactions responsible for the binding. In vivo studies demonstrated the ability of resveratrol at a dose of 40 mg/kg to reduce 11ß-HSD-1 activity in the liver of rats under conditions of experimental post-traumatic stress disorder (PTSD), as well as in non-stressed animals. In both cases, the resveratrol-induced reduction in 11ß-HSD-1 activity was accompanied by an increase in plasma corticosterone levels and a decrease in anxiety levels in the plus maze test.

Cerebral Blood Flow in Predator Stress-Resilient and -Susceptible Rats and Mechanisms of Resilience.

Stress-induced conditions are associated with impaired cerebral blood flow (CBF) and increased risk of dementia and stroke. However, these conditions do not develop in resilient humans and animals. Here the effects of predator stress (PS, cat urine scent, ten days) on CBF and mechanisms of CBF regulation were compared in PS-susceptible (PSs) and PS-resilient (PSr) rats. Fourteen days post-stress, the rats were segregated into PSs and PSr groups based on a behavior-related anxiety index (AI). CBF and its endothelium-dependent changes were measured in the parietal cortex by laser Doppler flowmetry. The major findings are: (1) PS susceptibility was associated with reduced basal CBF and endothelial dysfunction. In PSr rats, the basal CBF was higher, and endothelial dysfunction was attenuated. (2) CBF was inversely correlated with the AI of PS-exposed rats. (3) Endothelial dysfunction was associated with a decrease in eNOS mRNA in PSs rats compared to the PSr and control rats. (4) Brain dopamine was reduced in PSs rats and increased in PSr rats. (5) Plasma corticosterone of PSs was reduced compared to PSr and control rats. (6) A hypercoagulation state was present in PSs rats but not in PSr rats. Thus, potential stress resilience mechanisms that are protective for CBF were identified.

Mechanisms of Susceptibility and Resilience to PTSD: Role of Dopamine Metabolism and BDNF Expression in the Hippocampus.

Susceptibility and resilience to post-traumatic stress disorder (PTSD) are recognized, but their mechanisms are not understood. Here, the hexobarbital sleep test (HST) was used to elucidate mechanisms of PTSD resilience or susceptibility. A HST was performed in rats 30 days prior to further experimentation. Based on the HST, the rats were divided into groups: (1) fast metabolizers (FM; sleep duration < 15 min); (2) slow metabolizers (SM; sleep duration ≥ 15 min). Then the SM and FM groups were subdivided into stressed (10 days predator scent, 15 days rest) and unstressed subgroups. Among stressed animals, only SMs developed experimental PTSD, and had higher plasma corticosterone (CORT) than stressed FMs. Thus, resilience or susceptibility to PTSD was consistent with changes in glucocorticoid metabolism. Stressed SMs had a pronounced decrease in hippocampal dopamine associated with increased expressions of catecholamine-O-methyl-transferase and DA transporter. In stressed SMs, a decrease in monoaminoxidase (MAO) A was associated with increased expressions of hippocampal MAO-A and MAO-B. BDNF gene expression was increased in stressed FMs and decreased in stressed SMs. These results demonstrate relationships between the microsomal oxidation phenotype, CORT concentration, and anxiety, and they help further the understanding of the role of the liver−brain axis during PTSD.

Cardiac injury in rats with experimental posttraumatic stress disorder and mechanisms of its limitation in experimental posttraumatic stress disorder-resistant rats.

Traumatic stress causes posttraumatic stress disorder (PTSD). PTSD is associated with cardiovascular diseases and risk of sudden cardiac death in some subjects. We compared effects of predator stress (PS, cat urine scent, 10 days) on mechanisms of cardiac injury and protection in experimental PTSD-vulnerable (PTSD) and -resistant (PTSDr) rats. Fourteen days post-stress, rats were evaluated with an elevated plus-maze test, and assigned to PTSD and PTSDr groups according to an anxiety index calculated from the test results. Cardiac injury was evaluated by: 1) exercise tolerance; 2) ECG; 3) myocardial histomorphology; 4) oxidative stress; 5) pro- and anti-inflammatory cytokines. Myocardial heat shock protein 70 (HSP70) was also measured. Experimental PTSD developed in 40% of rats exposed to PS. Exercise tolerance of PTSD rats was 25% less than control rats and 21% less than PTSDr rats. ECG QRS, QT, and OTc intervals were significantly longer in PTSD rats than in control and PTSDr rats. Only cardiomyocytes of PTSD rats had histomorphological signs of metabolic and hypoxic injury and impaired contractility. Oxidative stress markers were higher in PTSD than in PTSDr rats. Pro-inflammatory IL-6 was higher in PTSD rats than in control and PTSDr rats, and anti-inflammatory IL-4 was lower in PTSD than in control and PTSDr rats. Myocardial HSP70 was lower in PTSD rats than in PTSDr and control rats. Our conclusion was that rats with PTSD developed multiple signs of cardiac injury. PTSDr rats were resistant also to cardiac injury. Factors that limit cardiac damage in PS rats include reduced inflammation and oxidative stress and increased protective HSP70.NEW & NOTEWORTHY For the first time, rats exposed to stress were segregated into experimental PTSD (ePTSD)-susceptible and ePTSD-resistant rats. Cardiac injury, ECG changes, and impaired exercise tolerance were more pronounced in ePTSD-susceptible rats. Resistance to ePTSD was associated with decreased inflammation and oxidative stress and with increased protective heat shock protein 70. Results may help identify individuals at high risk of PTSD and also provide a foundation for developing preventive and therapeutic means to restrict PTSD-associated cardiac morbidity.

Intermittent Hypoxic Conditioning Alleviates Post-Traumatic Stress Disorder-Induced Damage and Dysfunction of Rat Visceral Organs and Brain.

Posttraumatic stress disorder (PTSD) causes mental and somatic diseases. Intermittent hypoxic conditioning (IHC) has cardio-, vaso-, and neuroprotective effects and alleviates experimental PTSD. IHC's ability to alleviate harmful PTSD effects on rat heart, liver, and brain was examined. PTSD was induced by 10-day exposure to cat urine scent (PTSD rats). Some rats were then adapted to 14-day IHC (PTSD+IHC rats), while PTSD and untreated control rats were cage rested. PTSD rats had a higher anxiety index (AI, X-maze test), than control or PTSD+IHC rats. This higher AI was associated with reduced glycogen content and histological signs of metabolic and hypoxic damage and of impaired contractility. The livers of PTSD rats had reduced glycogen content. Liver and blood alanine and aspartate aminotransferase activities of PTSD rats were significantly increased. PTSD rats had increased norepinephrine concentration and decreased monoamine oxidase A activity in cerebral cortex. The PTSD-induced elevation of carbonylated proteins and lipid peroxidation products in these organs reflects oxidative stress, a known cause of organ pathology. IHC alleviated PTSD-induced metabolic and structural injury and reduced oxidative stress. Therefore, IHC is a promising preventive treatment for PTSD-related morphological and functional damage to organs, due, in part, to IHC's reduction of oxidative stress.

Correction to: Posttraumatic Stress Disorder Disturbs Coronary Tone and Its Regulatory Mechanisms.

The original version of this article unfortunately contained a mistake in the co-author name.

Intermittent hypoxia improves behavioral and adrenal gland dysfunction induced by posttraumatic stress disorder in rats.

Nonpharmacological treatments of stress-induced disorders are promising, since they enhance endogenous stress defense systems, are free of side effects, and have few contraindications. The present study tested the hypothesis that intermittent hypoxia conditioning (IHC) ameliorates behavioral, biochemical, and morphological signs of experimental posttraumatic stress disorder (PTSD) induced in rats with a model of predator stress (10-day exposure to cat urine scent, 15 min daily followed by 14 days of stress-free rest). After the last day of stress exposure, rats were conditioned in an altitude chamber for 14 days at a 1,000-m simulated altitude for 30 min on day 1 with altitude and duration progressively increasing to 4,000 m for 4 h on day 5. PTSD was associated with decreased time spent in open arms and increased time spent in closed arms of the elevated X-maze, increased anxiety index, and increased rate of freezing responses. Functional and structural signs of adrenal cortex degeneration were also observed, including decreased plasma concentration of corticosterone, decreased weight of adrenal glands, reduced thickness of the fasciculate zone, and hydropic degeneration of adrenal gland cells. The thickness of the adrenal fasciculate zone negatively correlated with the anxiety index. IHC alleviated both behavioral signs of PTSD and morphological evidence of adrenal cortex dystrophy. Also, IHC alone exerted an antistress effect, which was evident from the increased time spent in open arms of the elevated X-maze and a lower number of rats displaying freezing responses. Therefore, IHC of rats with experimental PTSD reduced behavioral signs of the condition and damage to the adrenal glands. NEW & NOTEWORTHY Intermittent hypoxia conditioning (IHC) has been shown to be cardio-, vaso-, and neuroprotective. For the first time, in a model of posttraumatic stress disorder (PTSD), this study showed that IHC alleviated both PTSD-induced behavioral disorders and functional and morphological damage to the adrenal glands. Also, IHC alone exerted an antistress effect. These results suggest that IHC may be a promising complementary treatment for PTSD-associated disorders.

Posttraumatic Stress Disorder Disturbs Coronary Tone and Its Regulatory Mechanisms.

Posttraumatic stress disorder (PTSD) is associated with myocardial injury, but changes in coronary regulatory mechanisms in PTSD have not been investigated. This study evaluated the effect of PTSD-inducing stress on coronary tone and its regulation by nitric oxide (NO) and voltage-gated K+ channels. PTSD was induced by exposing rats to predator stress, 15 min daily for 10 days, followed by 14 stress-free days. Presence of PTSD was confirmed by the elevated plus-maze test. Coronary tone was evaluated from changes in coronary perfusion pressure of Langendorff isolated hearts. Predator stress induced significant decreases in coronary tone of isolated hearts and in blood pressure of intact rats. L-NAME, a non-selective NO synthase (NOS) inhibitor, but not S-MT, a selective iNOS inhibitor, and increased coronary tone of control rats. In PTSD rats, both L-NAME and S-MT increased coronary tone. Therefore, the stress-induced coronary vasodilation resulted from NO overproduction by both iNOS and eNOS. NOS induction was apparently due to systemic inflammation as evidenced by increased serum interleukin-1ß and C-reactive protein in PTSD rats. Decreased corticosterone in PTSD rats may have contributed to inflammation and its effect on coronary tone. PTSD was also associated with voltage-gated K+ channel dysfunction, which would have also reduced coronary tone.

The role of microsomal oxidation in the regulation of monoamine oxidase activity in the brain and liver of rats.

It has been shown in our previous study that monoamine oxidase (MAO) activity in different brain regions are correlated with a microsomal oxidation phenotype. The data obtained in this study, using the microsomal oxidation inhibitor SKF525, and using animals with different duration of hexobarbital sleep, has shown that increased intensity of microsomal oxidation might be associated with increased MAO activity. Since the rats with short hexobarbital sleep time had higher content of hepatic microsomal cytochrome P450 than did rats with long hexobarbital sleep time. In addition, the rats with higher hepatic content of CYP450 had higher activities of MAO-A and MAO-B. Moreover, the microsomal oxidation inhibitor SKF-525 reduced brain and liver activities of MAOA and MAO-B. Consequently, MAO activities in a brain and a liver depend on the microsomal oxidation process.

Predicting anxiety responses to halogenated glucocorticoid drugs using the hexobarbital sleep time test.

Glucocorticoids (GCs) are used to treat numerous diseases, but their use in limited by adverse side effects. One such effect is occasional increased anxiety. Since the intensity of hepatic microsomal oxidation has been shown to alter responses to GC, we examined the possibility that rats with lower rates of hepatic GC metabolism would have increased anxiety. We hypothesized that the resulting, excessive GC would stimulate brain monoamine oxidase A (MAO-A), which would reduce brain serotonin, and thereby increase anxiety. Hepatic microsomal oxidative intensity was evaluated by the hexobarbital sleep time (HST) test. Results showed that rats with lower rates of hepatic GC metabolism had elevated brain MAO-A activity, reduced brain serotonin, and more anxiety than rats with higher rates of hepatic GC metabolism. We suggest that the HST test, as an integrative test of microsomal oxidation status, should be useful for predicting individual sensitivity to GC and to other drugs metabolized by the hepatic microsomal oxidation system.

Duration of hexobarbital-induced sleep and monoamine oxidase activities in rat brain: Focus on the behavioral activity and on the free-radical oxidation.

The present study is focused on the relationship between monoamine oxidase (MAO) activity and hepatic content of cytochrome P450 (CYP), which reflects the status of microsomal oxidation. For vital integrative evaluation of hepatic microsomal oxidation in rats, the hexobarbital sleep test was used, and content of CYP was measured in hepatic microsomes. Rats with short hexobarbital sleep time (SHST) had higher content of microsomal CYP than rats with long hexobarbital sleep time (LHST). Whole brain MAO-A and MAO-B activities, serotonin and carbonylated protein levels were higher in SHST than in LHST rats. MAO-A and MAO-B activities were higher in brain cortex of SHST rats; MAO-A activity was higher only in hypothalamus and medulla of LHST. The same brain regions of LHST rats had higher concentrations of carbonylated proteins and lipid peroxidation products than in SHST rats. MAO activity was correlated with microsomal oxidation phenotype. Rats with higher hepatic content of CYP had higher activities of MAO-A and MAO-B in the brain and higher plasma serotonin levels than rats with lower microsomal oxidation. In conclusion, data obtained in this study showed a correlation between MAO activity and microsomal oxidation phenotype.