Chronic Unpredictable Stress Model Research Articles

Levels of Corticosterone and Glucose in Blood of Rats under Conditions of Chronic Unpredictable Stress of Different Duration

INTRODUCTION: Mammals are almost constantly exposed to a variety of stressors. The changes in the concentration of corticosterone and the level of glucose in blood of animals under such conditions seems relevant for understanding the influence of repeated stress effects on endocrine and metabolic processes. AIM: To study the concentrations of corticosterone and glucose in blood of rats in different time periods of prolonged low-intensity unpredictable stress. MATERIALS AND METHODS: Experiments were carried out on 42 male Wistar rats. Individuals of the experimental groups were subjected to 7-day cycles of alternating stressors using a modified model of chronic unpredictable mild stress with presentation of different stressors. The concentration of corticosterone and glucose in blood was determined at 1, 2, 3 and 4 weeks of observation. RESULTS: A pronounced decrease in corticosterone levels was found in rats at 1 week of stress exposure, followed by a slow recovery by the end of 4th week. Blood glucose level increased at 2 weeks of exposure. CONCLUSION: The data obtained illustrate the specificity of changes in the levels of glucose and corticosterone in the blood of mammals in different time periods of chronic stress. These changes characterize the dysregulation of the integrative physiological systems in relatively early periods of chronic stress with the subsequent development of adaptation in the later stages of repeated stress exposures.

Levels of Corticosterone and Glucose in Blood of Rats under Conditions of Chronic Unpredictable Stress of Different Duration

INTRODUCTION: Mammals are almost constantly exposed to a variety of stressors. The changes in the concentration of corticosterone and the level of glucose in blood of animals under such conditions seems relevant for understanding the influence of repeated stress effects on endocrine and metabolic processes. AIM: To study the concentrations of corticosterone and glucose in blood of rats in different time periods of prolonged low-intensity unpredictable stress. MATERIALS AND METHODS: Experiments were carried out on 42 male Wistar rats. Individuals of the experimental groups were subjected to 7-day cycles of alternating stressors using a modified model of chronic unpredictable mild stress with presentation of different stressors. The concentration of corticosterone and glucose in blood was determined at 1, 2, 3 and 4 weeks of observation. RESULTS: A pronounced decrease in corticosterone levels was found in rats at 1 week of stress exposure, followed by a slow recovery by the end of 4th week. Blood glucose level increased at 2 weeks of exposure. CONCLUSION: The data obtained illustrate the specificity of changes in the levels of glucose and corticosterone in the blood of mammals in different time periods of chronic stress. These changes characterize the dysregulation of the integrative physiological systems in relatively early periods of chronic stress with the subsequent development of adaptation in the later stages of repeated stress exposures.

NADPH mimics the antidepressant effects of exercise in a chronic unpredictable stress rat model

Exercise is known to be an effective intervention for depression. NADPH has been demonstrated to have neuroprotective effects in our previous studies. This study aimed to investigate if NADPH has antidepressant effects and can mimic the effects of exercise in a chronic unpredictable stress (CUS) rat model. CUS rats underwent an 8-week swimming exercise (30 min/d, 5d/w) or were intraperitoneally administered 4 mg/kg or 8 mg/kg NADPH. The open field test (OFT), sucrose preference test (SPT), novelty-suppressed feeding test (NSFT), and forced swimming test (FST) were used to examine the antidepressant-like behaviors of the rats. Exercise, 4 mg/kg, and 8 mg/kg NADPH similarly reduced anxiety, as demonstrated by the number of fecal pellets. Meanwhile, exercise and 8 mg/kg NADPH significantly increased locomotion activity in the OFT. Exercise, 4 mg/kg, and 8 mg/kg NADPH effectively reversed CUS-induced anhedonia in rats in the SPT. Exercise, 4 mg/kg, and 8 mg/kg NADPH had no impact on appetite of depressed rats; however, 8 mg/kg NADPH increased the rats’ exploratory activity in the NSFT. Exercise, 4 mg/kg, and 8 mg/kg NADPH significantly reduced the immobility time of CUS model rats, while exercise and 8 mg/kg NADPH postponed the early CUS-induced "immobility" in the FST. These results demonstrated that NADPH has similar antidepressant-like effects to exercise in CUS-induced depression model rats and is a potential exercise-mimicking antidepressant.

NMT2 alleviates depression-like behavior in a rat model of chronic unpredictable stress: An integrated proteomic and phosphoproteomic analysis

Proteomics has been widely used to investigate multiple diseases. Combining the analyses of proteomics with phosphoproteomics can be used to further explain the pathological mechanisms of depression. In this study, depression-like behavior was induced in a rat model of chronic unpredictable mild stress (CUMS). We subsequently conducted the sucrose preference test, open field experiment, and forced swimming test to assess depressive-like behavior. Proteomic and phosphoproteomic sequencing of the hippocampal tissues from depressive-like behavior and normal rats were analyzed to identify differentially expressed proteins (DEPs) and differentially phosphorylated proteins (DPPs). Differentially expressed phosphorylated proteins (DEPPs) were obtained by intersecting the DEPs and DPPs, and functional enrichment analysis, as well as ingenuity pathway analysis (IPA), were subsequently performed. The study also investigated correlations among the DEPPs and used qRT-PCR to quantify the expression levels of key genes. Five DEPPs were identified, Gys1, Nmt2, Lrp1, Bin1, and Atp1a1, which were found to activate the synaptogenesis signaling pathway, induce mitochondrial dysfunction, and activate the phosphoinositide biosynthesis and degradation pathways. The qRT-PCR results confirmed the proteomic findings for Gys1, Nmt2, Lrp1, and Atp1a1. Importantly, inhibiting Nmt2 was found to alleviate depression-like behavior and alleviate neuronal apoptosis in the hippocampus of CUMS rats. In conclusion, we identified five DEPPs associated with the synaptogenesis signaling pathway, mitochondrial dysfunction, and phosphoinositide biosynthesis and degradation in depression. Furthermore, NMT2 may be a potential target for the treatment or diagnosis of depression. Our findings provide novel insights into the molecular mechanisms of depression.

Sex- Specific Effects of Chronic Unpredictable Stress on Renal Mitochondrial Function in C57BL/6 Mice

Background: The kidneys play a central role in long term control of blood pressure. Chronic psychological stress has been linked to hypertension, inflammation, and is associated with both an increased prevalence and progression of renal disease. However, the molecular and cellular mechanisms by which chronic stress alters renal function are not fully understood, and data on sex specific differences in renal and blood pressure responses to stress are limited. The impact of stress to cause local inflammation and mitochondrial dysfunction in the kidneys is not clear and represents a potential mechanism leading to renal dysfunction and hypertension. The chronic unpredictable stress (CUS) model induces psychological stress in rodents thus allowing the study of integrated physiological changes to the kidney in response to stress. Hypothesis: Exposing mice to CUS will lead to increased blood pressure that is associated with decreased renal mitochondrial function and renal inflammation. Methods: To investigate the link between stress, renal mitochondrial function, inflammation, and blood pressure, we exposed adult male and female C57BL/6 mice to CUS for 28 consecutive days. Blood pressure was measured via tail cuff on the 28th day of stress. 24 hours later, mice were euthanized and estrous cycle phase in females was determined by vaginal cytology. Kidney mitochondrial oxygen consumption was assessed using the Oroboros respirometer on the pole ends of the left kidneys. NLR family pyrin domain containing 3 (NLRP3) expression was measured in the right kidney using Real-Time TaqMan PCR. Results: Mean arterial pressure was elevated in both stressed males (in mmHg, 106±4 vs 87±4, n<11, p<0.01) and females (131± 6 vs 94±11 n<4, p<0.01) compared to non-stressed mice. While maximal electron transport capacity (ETS), a measure of mitochondrial function, was unchanged in CUS male kidneys, stressed females in the receptive (estrus and proestrus) phase of the estrous cycle exhibited a significant decrease in renal ETS compared to non-stressed females (in pmol O2/mg protein, 14.4±0.9 vs 11.4±0.7, n=11, p<0.05). Renal mRNA expression of NLRP3 was increased in CUS males (35%± 7.7, n=8, p<0.01) but unchanged in CUS females. Conclusion: These data suggest potential mechanistic differences in stress-induced hypertension in renal mitochondria (decreased ETS in stressed females) and inflammasome level (increased NLRP3 in stressed males) between male and female mice. This work was supported by P20GM109091 (F.H.), R01HL130972-01A1, R01HL5949, BX000168-10A1, BX005320 (F.G.S.), R01DK132948 (C.W. & F.P.) R01 MH129798 (SKW); VA VISN7 RDA (F.H.),, 1U54HL169191-01 & BX002604 (M.J.R.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the abstract. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mechanism of Jiaotai Pills in treatment of depression by UHPLC-TOF-MS combined with network pharmacology and experimental validation

This study aims to analyze the constituents of Jiaotai Pills migrating to the blood in normal rats by UHPLC-TOF-MS technique and reveal the underlying mechanism of Jiaotai Pills in the treatment of depression by network pharmacology and animal experiments. UHPLC-TOF-MS technique was used to detect the constituents of Jiaotai Pills in the blood of rats after intragastric administration. The intersection target of the constituents and depression was screened by DisGeNET and SwissTargetPrediction database, and the protein-protein interaction(PPI) network was constructed. Key targets were imported into the DAVID platform for Gene Ontology(GO) analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway annotation. Combined with constituents, targets, and pathways, the "constituent-target-pathway" network was constructed by Cytoscape 3.9.1 software, through which the key targets and pathways of Jiaotai Pills against depression were predicted. The depression model of chronic unpredictable mild stress(CUMS) was established on rats. After that, behavioral experiments were conducted. The expression of inflammatory factors in serum and the neurotransmitters in the brain were detected by ELISA, and the expression of key targets in the hippocampus was detected by Western blot. The results showed that a total of 17 constituents of Jiaotai Pills were identified in the blood, including 10 alkaloids. There were 124 intersection targets between constituents of Jiaotai Pills and depression disorder. A total of 52 core targets were screened according to PPI results, including NLRP3 and caspase-1, etc. KEGG enrichment analysis mainly involved 15 typical pathways such as NOD-like receptor pathway. The results of animal experiments showed that Jiaotai Pills significantly improved the depression-like behavior of CUMS depressive model on rats, decreased the levels of IL-1β, TNF-α and IL-6 in serum, and increased the expression of neurotransmitters such as 5-hydroxytryptamine(5-HT), dopamine(DA), and norepinephrine(NE) in the brain. Besides, Jiaotai Pills also down-regulated the expression of NLRP3 and caspase-1 proteins in the hippocampus and inhibited the NLRP3-mediated NOD-like receptor signaling pathway. In conclusion, Jiaotai Pills may play a role in the treatment of depression by inhibiting the NLRP3 inflammasome and the NOD-like receptor pathway mediated by NLRP3.

Hypothalamic Gene Expression in a Rat Model of Chronic Unpredictable Mild Stress Treated with Electroacupuncture.

Depression is characterized by the loss of pleasure and a depressed mood, and it is a common mental disorder in the twenty-first century. Multiple gene imbalances, which are considered pathological factors in depression, were detected in the brain. Electroacupuncture is an effective therapeutic approach for depression that has minimal side effects. As a crucial structure in the hypothalamus-pituitary-adrenal, the hypothalamus plays a key role in depression. Our study focused on the transcriptome level in the hypothalamus of depressive rats. After chronic unpredictable mild stress, the rats exhibited depressive-like behaviors, such as decreased sucrose consumption in the SPT, increased time in the central area of the OFT and increased immobility in the FST. Moreover, electroacupuncture alleviated depressive behaviors. Because of the importance of the hypothalamus in depression, we next detected gene expression in the hypothalamus. A total of 510 genes (125 upregulated genes and 385 downregulated genes) were detected in the hypothalamus of depressive rats. 15 of the 125 upregulated genes and 63 of the 385 downregulated genes could be altered by electroacupuncture, which suggests the antidepressant effect of electroacupuncture. Our study also provided the evidence that regulation of transcriptome in the hypothalamus might be a potential mechanism of electroacupuncture treatment.

Integrative proteomics and metabolomics data analysis exploring the mechanism of brain injury after cardiac surgery in chronic stress rats

ObjectivePreoperative chronic stress (CS) is associated with postoperative brain injury in patients undergoing open heart cardiac surgery. This research is to explore the potential molecular biological mechanisms of brain damage following cardiac surgery in preoperative CS rats by the analyses combining proteomics and metabolomics.MethodsWe constructed the chronic unpredictable stress (CUS) and cardiac surgery models in adult rats. We proved the brain injury in CUS cardiac surgery rats by Hematoxylin–Eosin (H&E) staining, followed by separating the hippocampal tissue and investigating the potential mechanisms of brain injury by the methods of data-independent acquisition proteomics and untargeted metabolomics.ResultsThe signaling pathways of glycoproteins and metabolism of amino acids were the main possible mechanisms of brain injury in CUS rats following cardiac surgery according to the proteomics and metabolomics. In addition, the pathways of animo acids metabolism such as the pathways of lysine degradation and β-alanine metabolism may be the main mechanism of cardiac surgery related brain injury in preoperative CUS rats.ConclusionsThe pathways of animo acids metabolism such as lysine degradation and β-alanine metabolism may be the potential mechanisms of brain injury in CUS rats following cardiac surgery. We should focus on the varieties of bioproteins and metabolites in these pathways, and related changes in other signaling pathways induced by the two pathways.

Antidepressant effects of esketamine via the BDNF/AKT/mTOR pathway in mice with postpartum depression and their offspring

Postpartum depression (PPD) is a serious mental health problem that can negatively affect future generations. BDNF/AKT/mTOR signaling in the frontal lobe and hippocampus in mice is associated with depression, but its role in mice with PPD and their offspring is unknown. This study was aimed at investigating the effects of esketamine (ESK), a drug approved for treatment of refractory depression, on the BDNF/AKT/mTOR pathway in mice with PPD and their offspring. A model of chronic unpredictable mild stress with pregnancy was used. ESK was injected into postpartum mice, and behavioral tests were conducted to predict the severity of symptoms at the end of lactation and in the offspring after adulthood. Both mice with PPD and their offspring showed significant anxiety- and depression-like behaviors that were ameliorated with the ESK intervention. ESK enhanced exploratory behavior in unfamiliar environments, increased the preference for sucrose, and ameliorated the impaired BDNF/AKT/mTOR signaling in the frontal and hippocampal regions in mice. Thus, ESK may have great potential in treating PPD and decreasing the incidence of depression in offspring.

Prolonged stress response induced by chronic stress and corticosterone exposure causes adult neurogenesis inhibition and astrocyte loss in mouse hippocampus

Chronic stress is a pervasive and complex issue that contributes significantly to various mental and physical health disorders. Using the previously established chronic unpredictable stress (CUS) model, which simulates human stress situations, it has been shown that chronic stress induces major depressive disorder (MDD) and memory deficiency. However, this established model is associated with several drawbacks, such as limited research reproducibility and the inability to sustain stress response. To resolve these issues, we developed a new CUS model (CUS+C) that included exogenous corticosterone exposure to induce continuous stress response. Thereafter, we evaluated the effect of this new model on brain health. Thus, we observed that the use of the CUS+C model decreased body and brain weight gain and induced an uncontrolled coat state as well as depressive-like behavior in adult mice. It also impaired learning memory function and cognitive abilities, reduced adult hippocampal neurogenesis as well as the number of hippocampal astrocytes, and downregulated glial fibrillary acidic protein expression in the brains of adult mice. These findings can promote the utilization and validity of the animal stress model and provide new information for the treatment of chronic stress-induced depressive and memory disorders.

Pogostemon cablin essential oil affects anxiety- and depressive-like behaviors and the gut microbiota in chronic unpredictable mild stress model rats.

The gut microbiota is thought to be an important factor that influences brain processes and behaviors through the gut-brain axis. Pogostemon cablin is used in traditional Chinese medicine (TCM) to treat gastrointestinal symptoms. Patchouli essential oil (PCO), the main active agent in P. cablin, is used in aromatherapy for stress relief. The aim of our study was to investigate the effects of orally administered PCO on anxiety- and depressive-like behaviors and the gut microbiota. We constructed a rat model of chronic unpredictable mild stress (CUMS) and explored the anxiolytic- and antidepressant-like effects of PCO using the open field test (OFT) and forced swim test (FST). Changes in the abundance of the gut microbiota, short-chain fatty acids (SCFAs), and other related molecules were assessed to determine the role of the gut microbiota. Our results showed that CUMS induced an anxiety-like phenotype in the OFT, which was reversed by PCO, and that PCO also significantly mitigated the depression-like behaviors caused by CUMS in the FST. Furthermore, we found that PCO increased the relative abundances of several probiotics, including Bacteroides and Blautia, and decreased the relative abundances of Ruminococcus_1 and Ruminococcus_2, which were increased by CUMS. Regarding SCFAs, the metabolites of the gut microbiota, PCO increased the concentration of propionic acid and decreased that of caproic acid. Finally, PCO restored the serotonin (5-hydroxytryptamine, 5-HT) level in the hippocampus, which had been decreased by CUMS. The results of this study suggested that PCO can improve stress-related anxiety- and depression-like behaviors and might exert its effects on the central nervous system through interactions with the gut microbiota.

Parental preconception stress in zebrafish induces long-lasting anxiety in offspring

The growth and function of the vertebrate brain are impacted by environmental stimuli and early life stress. Adults who experience chronic stress during early life are more likely to suffer various neurodevelopmental and health issues. However, our understanding of how these specific environmental signals at different developmental stages affect brain development is poorly understood. In this study, we investigated if stress in parents prior to conception modulates neurodevelopment in offspring. We used a chronic unpredictable stress model adapted to zebrafish, which is an increasingly popular vertebrate model in neuroscience research to investigate the effects of both maternal and paternal preconception stress on offspring behavior. We evaluated the responsiveness of three anxiety-related behavioral paradigms in zebrafish: the novel tank test, thigmotaxis, and shoaling behavior. We found larvae from stressed females exhibited anxiety-like behavior in a thigmotaxis assay. As these larvae matured into adults, they continued to exhibit anxiety-like behavior in a novel tank and shoaling behavioral assay. These studies indicate preconception stress exposure in parents can induce life-long alterations in offspring neurodevelopment. Further, these results expand the hypothesis that chronically elevated glucocorticoid signaling not only in stressed mothers, but also stressed dads can affect neurodevelopment in offspring. We propose that zebrafish may be a useful model to study the transgenerational effects of chronic stress mediated via the maternal and paternal line.

Saikosaponin a alleviates depressive-like behavior by regulating the BDNF-TrkB-CREB signaling pathway in a mouse model of chronic unpredictable mild stress

Saikosaponin a alleviates depressive-like behavior by regulating the BDNF-TrkB-CREB signaling pathway in a mouse model of chronic unpredictable mild stress

Acupuncture alleviates CUMS-induced depression-like behaviors of rats by regulating oxidative stress, neuroinflammation and ferroptosis

BackgroundThe treatment of depression with acupuncture has been documented. The mechanism behind acupuncture's curative and preventative effects is still unknown. MethodsThe current study examined the effects of acupuncture on depression-like behaviors in a rat model of chronic unpredictable mild stress (CUMS), while also exploring its potential mechanisms. A total of six groups of rats were randomly assigned: control, CUMS, acupuncture, fluoxetine, acupoint catgut embedding and sham acupoint catgut embedding. Fluoxetine (2.1 mg/kg) and acupoint catgut embedding were used for comparative research to acupuncture. The modelling evaluation is measured by body weight and behavior tests. Western blotting and reverse transcription-polymerase chain reaction were used to detect the proteins and mRNA expression of Silent information regulator 1 (Sirt1)/ nuclear factor-erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1)/ Glutathione peroxidase 4 (GPX4) pathway in the hippocampus. The expression of oxidative stress (OS)-related proteins and inflammatory cytokines in the serum was detected with ELISA. Immunofluorescence showed microglia and astrocytes activity in the hippocampus. ResultsAcupuncture and fluoxetine could alleviate CUMS-induced depression-like behaviors. Acupuncture was also found to effectively reverse the levels of MDA, SOD, GSH, GSH-PX and T-AOC, IL-1β, IL-6 and TNF-α in the serum of CUMS-induced rats. Rats with CUMS showed decreased levels of Sirt1, Nrf2, HO-1 and GPX4 in the hippocampus, while acupuncture treatment could partly reverse the diminished effects. In addition, acupuncture treatment significantly reduced the activation of hippocampal microglia and astrocytes in CUMS-induced rats. ConclusionThe study's findings indicate that acupuncture has the potential to mitigate depression-like behaviors in rats induced with CUMS by mitigating OS and reducing neuroinflammation.

Protective effects of vitamin D3 on depressive manifestations in rat model of chronic unpredictable mild stress

Protective effects of vitamin D3 on depressive manifestations in rat model of chronic unpredictable mild stress

Mechanism of Jiaotai Pills in treatment of depression based on quantitative proteomics

This study aimed to investigate the effect of Jiaotai Pills on protein expression in the hippocampus of the rat model of chronic unpredictable mild stress(CUMS)-induced depression by quantitative proteomics and explore the anti-depression mechanism of Jiaotai Pills. The SD rats were randomized into control, model, Jiaotai Pills, and fluoxetine groups(n=8). Other groups except the control group were subjected to CUMS modeling for 4 weeks. After 4 weeks of continuous administration, the changes of behavior and pathological morphology of the hippocampal tissue were observed. Proteins were extracted from the hippocampal tissue, and bioinformatics analysis was performed for the differentially expressed proteins(DEPs) identified by quantitative proteomics. Western blot was employed to verify the key DEPs. The results showed that Jiaotai Pills significantly alleviated the depression behaviors and hippocampal histopathological changes in the rat model of CUMS-induced depression. A total of 5 412 proteins were identified in the hippocampus of rats, including 65 DEPs between the control group and the model group and 35 DEPs between the Jiaotai Pills group and the model group. There were 16 DEPs with the same trend in the Jiaotai Pills group and the control group, which were mainly involved in sphingolipid, AMPK, and dopaminergic synapse signaling pathways. The Western blot results of Ppp2r2b, Cers1, and Ndufv3 in the hippocampus were consistent with the results of proteomics. In conclusion, Jiaotai Pills may play an anti-depression role by modulating the levels of Ppp2r2b, Cers1, Ndufv3 and other proteins and regulating sphingolipid, AMPK, and dopaminergic synapse signaling pathways.

Deep brain stimulation of ventromedial prefrontal cortex reverses depressive-like behaviors via BDNF/TrkB signaling pathway in rats

AimDeep brain stimulation (DBS) is currently under investigation as a potential therapeutic approach for managing major depressive disorder (MDD) and ventromedial prefrontal cortex (vmPFC) is recognized as a promising target region. Therefore, the present study aimed to investigate a preclinical paradigm of bilateral vmPFC DBS and examine the molecular mechanisms underlying its antidepressant-like effects using chronic unpredictable stress (CUS) model in rats. Main methodsMale rats were subjected to stereotaxic surgery and deep brain stimulation paradigm in non-stressed and CUS rats respectively, and the therapeutic effect of DBS were assessed by a series of behavioral tests including sucrose preference test, open field test, elevated plus maze test, and forced swim test. The potential involvement of the BDNF/TrkB signaling pathway and its downstream effects in this process were also investigated using western blot. Key findingsWe identified that a stimulation protocol consisting of 130 Hz, 200 μA, 90 μs pulses administered for 5 h per day over a period of 7 days effectively mitigated CUS-induced depressive-like and anxiety-like behaviors in rats. These therapeutic effects were associated with the enhancement of the BDNF/TrkB signaling pathway and its downstream ERK1/2 activity. SignificanceThese findings provide valuable insights into the potential clinical utility of vmPFC DBS as an approach of improving the symptoms experienced by individuals with MDD. This evidence contributes to our understanding of the neurobiological basis of depression and offers promise for the development of more effective treatments.

Chronic stress predisposes to the aggravation of inflammation in autoimmune diseases with focus on rheumatoid arthritis and psoriasis

The global incidence of autoimmune diseases is on the rise, and many healthcare professionals believe that chronic stress plays a prominent role in both the aggravation and remission of these conditions. It is believed that prolonged exposure to stress is associated with neuroimmune axis malfunction, which eventually dysregulates multiple immunological factors as well as deregulates autoimmune responses that play a central role in various autoimmune diseases, including rheumatoid arthritis and psoriasis. Herein, we performed validation of an 8-week long rat model of chronic unpredictable stress (CUS) which consisted of exposing groups of rats to random stressors daily for 8 weeks. Additionally, we developed a novel rat model combining 8-week long random stressor-induced CUS with CIA-triggered arthritis and IMQ-triggered psoriasis and have successfully used both these models to assess the role of chronic stress in the aggravation of arthritis and psoriasis, respectively. Notably, the 8-week CUS protocol extensively aggravated and prolonged both arthritis and psoriasis condition in the rat model by upregulating the release of different pro-inflammatory cytokines, dysregulation of immune cell responses and oxidative stress system, which were all related to severe inflammation. Further, CUS aggravated macroscopic features and the increase in destruction of joint tissue and epidermal thickness induced by CIA and IMQ, respectively, in rats. In conclusion, this study suggests that exposure to an 8-week long CUS paradigm aggravates the distinctive characteristics of rheumatoid arthritis and psoriasis in rats via amplifying the inflammatory circuits and immune cell responses linked to these autoimmune diseases.

Widely targeted metabolomics unveils baicalin-induced hippocampal metabolic alternations in a rat model of chronic unpredictable mild stress

Baicalin has various neuroprotective effects in models of nervous system disease. Our study has shown baicalin could alleviate depressive-like behaviors in a neuroendocrine mouse model. But the systematic metabolic characteristic and particular targets of baicalin in regulating depressive behaviors have never been investigated. Therefore, this study aims to reveal the hippocampal metabolic profiling of chronic unpredictable mild stress (CUMS) induced depressive rats and the potential metabolic variations after baicalin treatment. We first used the sucrose preference test and open field test to access the antidepressant effects of baicalin. Then, metabolites of the hippocampus after baicalin therapy were monitored by widely-targeted metabolomics based on ultra-performance liquid chromatography-tandem mass spectrometry technology. Finally, the potential mechanism associated with neurogenesis obtained from metabolomics was verified by immunohistochemistry. The results showed that baicalin(40,80 mg/kg) could significantly alleviate depressive behaviors induced by CUMS as demonstrated by an increase in sucrose preference and movement distance and stand-up times in open field test. In the metabolomic analysis, a total of 733 metabolites were identified after baicalin treatment including 15 differential metabolites such as organic acid and its derivatives, heterocyclic compounds, fatty acid, bile acids, amino acid and its metabolites, and so on. Enrichment for differential metabolites showed that the differential metabolites might be involved in the process of folate and cofactor biosynthesis, cholesterol metabolism, primary bile acid biosynthesis, tyrosine metabolism and dopaminergic synapse. Moreover, immunohistochemical analysis confirmed baicalin could facilitate hippocampal neurogenesis of depressive rats in CUMS model. These results suggested baicalin might exert antidepressant effects through regulating the differential metabolites which might play a crucial role in inhibiting oxidative stress and improving neurogenesis. Our findings wish to discover the potential mechanism of baicalin on depression from the metabolomics perspective and promote its clinical application.

Gastrodin improves nerve cell injury and behaviors of depressed mice through Caspase-3-mediated apoptosis.

We investigated the effects and target of gastrodin (GAS) for treating depression through network pharmacology combined with experimentation. The therapeutic target and signal of GAS for depression were analyzed by network pharmacology. Depression in mice was mimicked with a chronic unpredictable mouse stress (CUMS) model. Through open field, elevated plus maze, forced swimming, and tail suspension tests, the effects of GAS on the CUMS mice behaviors were examined, and the levels of neurotransmitters were detected. The histopathological changes were assayed by H&E and IHC staining, and the protein expressions were detected by Western blotting. Small molecule-protein docking and molecular dynamics experiments were conducted to simulate the binding mode between GAS and Caspase-3. Network pharmacological analysis revealed that Caspase-3 was the action target of GAS. GAS could improve depression-like behaviors in CUMS mice, elevate their neurotransmitter levels, ameliorate their nerve cell injury, and inhibit their Caspase-3 expression. After knocking out Caspase-3, the effects of GAS were inhibited. Molecular dynamics simulation and small molecule-protein docking found that GAS bound to Caspase-3 at SER25, inhibiting the maturation and activation of Caspase-3. We find that GAS can act as a Caspase-3 inhibitor, which improves depression-like behaviors and nerve cell injury in CUMS mice by inhibiting Caspase-3-mediated apoptosis.