Mild Stress Rat Research Articles

Nitric Oxide and Cyclic Guanosine Monophosphate Signaling Mediates the Antidepressant Effects of Acupuncture in the Rat Model of Chronic Unpredictable Mild Stress.

BackgroundDepression is a major mood disorder. Some patients have been reported to improve following acupuncture. This study aimed to investigate the effects of acupuncture on behaviors associated with depression in the chronic unpredictable mild stress (CUMS) rat model. The expression of signaling pathway components of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in the rat hippocampus and plasma were also measured.Material/MethodsMale Sprague-Dawley rats (N=40) were divided into the control group (N=10), the model group (N=10), the acupuncture group (N=10), and the non-acupuncture group (N=10). The rat model was established by orphaning combined with chronic unpredictable mild stress (CUMS) for six weeks. The acupuncture group was given 21 days of treatment using acupoints (AP) or non-acupoints (NP). Rat behaviors associated with depression were tested using the sucrose preference test (SPT), the open field test (OFT), and the elevated plus maze (EPM) test. Enzyme-linked immunoassay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the expression of inducible nitric oxide synthase (iNOS), neuronal nitric oxide synthase (nNOS), and the N-methyl-D-aspartate (NMDA) receptor subunits, NR1, NR2A, and NR2B in the rat plasma and hippocampus.ResultsAcupuncture reversed the behaviors associated with depression in the CUMS rat model and reduced the expression of components of the NO and cGMP pathway in the rat hippocampus and plasma.ConclusionsIn the CUMS rat model, treatment with acupuncture reduced behaviors associated with depression, and these effects were associated with changes in the NO and cGMP signaling pathway.

Pigment epithelium-derived factor alleviates depressive-like behaviors in mice by modulating adult hippocampal synaptic growth and Wnt pathway

Pigment epithelium-derived factor (PEDF, also known as SERPINF1) is a secreted glycoprotein with neuroprotective effects. However, the potential role of PEDF in major depressive disorder (MDD) remains largely unknown. Here, applying two-dimensional gel electrophoresis (2-DE) proteomics, we found that PEDF levels were significantly decreased in the plasma of 12 first-episode treatment-naïve MDD patients (FETND) compared to the levels in 12 healthy controls (HCs). PEDF levels were especially lower in MDD patients than in HCs and patients with bipolar disorder (BD) and schizophrenia (SCZ), and elevated PEDF were consistent with decreased HAM-D scores in patients given antidepressant therapy (ADT). Animal research indicated that PEDF was decreased in the periphery and hippocampus of two well-known depression rodent models (the chronic unpredictable mild stress (CUMS) rat model and chronic social defeat stress (CSDS) mouse model). Decreased PEDF levels in the hippocampus led to depressive-like behaviors, synaptic impairments and aberrant Wnt signaling in C57BL mice, while increased PEDF resulted in the opposite results. Mechanistic studies indicated that PEDF contributes to dendritic growth and Wnt signaling activation in the hippocampus of adult mice. Taken together, the results of our study demonstrate the involvement of PEDF and its related mechanism in depression, thus providing translational evidence suggesting that PEDF may be a novel therapeutic target for depression.

Hippocampal proteomic changes of susceptibility and resilience to depression or anxiety in a rat model of chronic mild stress

Chronic stressful occurrences are documented as a vital cause of both depression and anxiety disorders. However, the stress-induced molecular mechanisms underlying the common and distinct pathophysiology of these disorders remains largely unclear. We utilized a chronic mild stress (CMS) rat model to differentiate and subgroup depression-susceptible, anxiety-susceptible, and insusceptible rats. The hippocampus was analyzed for differential proteomes by combining mass spectrometry and the isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique. Out of 2593 quantified proteins, 367 were aberrantly expressed. These hippocampal protein candidates might be associated with susceptibility to stress-induced depression or anxiety and stress resilience. They provide the potential protein systems involved in various metabolic pathways as novel investigative protein targets. Further, independent immunoblot analysis identified changes in Por, Idh2 and Esd; Glo1, G6pdx, Aldh2, and Dld; Dlat, Ogdhl, Anxal, Tpp2, and Sdha that were specifically associated to depression-susceptible, anxiety-susceptible, or insusceptible groups respectively, suggesting that identical CMS differently impacted the mitochondrial and metabolic processes in the hippocampus. Collectively, the observed alterations to protein abundance profiles of the hippocampus provided significant and novel insights into the stress regulation mechanism in a CMS rat model. This might serve as the molecular basis for further studies that would contributed to a better understanding of the similarities and differences in pathophysiologic mechanisms underlying stress-induced depression or anxiety, and stress resiliency.

Ginsenoside Rg1 attenuates chronic unpredictable mild stress-induced depressive-like effect via regulating NF-κB/NLRP3 pathway in rats.

Ginsenoside (GS Rg1), which has neuroprotection and anti-inflammation activities, is the main active ingredient of Radix Ginseng. However, its antidepressant-like effect in rats remains unclear. Our study was conducted to investigate whether GS Rg1 confers an antidepressant effect in rats exposed to a chronic unpredictable mild stress model of depression and to explore its possible mechanisms. Our results revealed that GS Rg1 treatments for 3 weeks alleviated the depression-related behaviors of chronic unpredictable mild stress-exposed rats, as indicated by increasing sucrose preference, improving locomotor activity and shortening immobile time in both the forced swimming tests and tail suspension tests. And these ameliorative effects of GS Rg1 treatment were involved with regulating chronic unpredictable mild stress-induced pro-inflammatory cytokine interleukin beta (IL-1β) related neuro-inflammation. In addition, we further found that GS Rg1 reversed chronic unpredictable mild stress-induced IL-1β elevation, possibly by inhibiting nuclear factor kappa B pathway activation and regulating nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome expression. In short, our results suggested that GS Rg1 exerted a potential antidepressant-like effect in chronic unpredictable mild stress rat model of depression, which may provide an insight into the potential of GS Rg1 in therapeutic implications for depression.

Cerebellar Fastigial Nucleus Stimulation in a Chronic Unpredictable Mild Stress Rat Model Reduces Post-Stroke Depression by Suppressing Brain Inflammation via the microRNA-29c/TNFRSF1A Signaling Pathway.

BackgroundWe previously reported that cerebellar fastigial nucleus stimulation reduced post-stroke depression in a rat model by reducing inflammation. This study aimed to investigate the molecular inflammatory signaling pathways associated with cerebellar fastigial nucleus stimulation in an established rat model of post-stroke depression.Material/MethodsTwenty-four Sprague-Dawley rats included a sham group (N=6), an untreated stroke group (N=6), an untreated post-stroke depression model group (PSD) (N=6), and the model group treated with cerebellar fastigial nucleus stimulation (FNS) (N=6). The rat stroke model involved occlusion of the middle cerebral artery occlusion (MCAO). Post-stroke depression model was established using chronic unpredictable mild stress treatment and was verified using an open field test. Real-time polymerase chain reaction (PCR) and Western blot compared expression levels of microRNA-29c (miR-29c), miR-676, TNFRSF1A, tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in cerebellar tissue. U251 human glioblastoma cells and SH-SY5Y human neuroblastoma cells were studied in vitro.ResultsCerebellar fastigial nucleus stimulation reduced behaviors associated with depression in the rat model, upregulated the expression of miR-29c, and reduced the expression of TNFRSF1A and inflammatory cytokines, and mildly reduced neuronal apoptosis. Bioinformatics data analysis identified a regulatory relationship between miR-29c and TNFRSF1A. SH-SY5Y cells treated with a miR-29c mimic, or TNFRSF1A short interfering RNA (siRNA), identified a negative regulatory relationship between TNFRSF1A and miR-29c.ConclusionsIn a rat model, cerebellar fastigial nucleus stimulation reduced the expression of TNFRSF1A by upregulating miR-29c expression, which suppressed the expression of inflammatory cytokines, resulting in reduced severity of post-stroke depression.

Effects of regulating gut microbiota on the serotonin metabolism in the chronic unpredictable mild stress rat model.

ObjectiveThis study was to inspect the antidepressant‑like effect of prebiotics and probiotics, and to explore the effect of modulating gut microbiota on the serotonin (5‐HT) metabolism.MethodsFifty rats were separated into control and other four groups randomly. The four groups underwent the chronic unpredictable mild stress (CUMS) intervention with or without prebiotics and probiotics (Bifidobacterium longum, L. rhamnosus) treatment. After weighted, the animals underwent a series of behavioral tests comprising the sucrose preference test (SPT) and the forced swimming test (FST). Central and colonic serotonin levels and relative metabolism factors were measured and analyzed. Microbiota was examined by 16S rRNA gene pyrosequencing.ResultsCUMS intervention caused a decrease in body weight, an increase in FST, and a decrease in SPT. Prebiotics and probiotics all ameliorated the CUMS‐induced loss of weight and depressive‐like behaviors to a certain extent, especially L. rhamnosus. Compared with the group of CUMS intervention, the rats of probiotics and probiotics treatment had a tendency to reduce colonic 5‐HT and increase 5‐HT in frontal cortex and hippocampus. However, there was no significant difference in peripheral blood 5‐HT among these groups. Furthermore, CUMS caused noteworthy gut microbiota variations at the phylum and other levels in rats. Remarkably, there were considerable relations of perturbed gut microbiota with the changed metabolism of 5‐HT.ConclusionIn conclusion, these findings implied that prebiotics and probiotics have antidepressive effects, and a considerable effect on the regulation of 5‐HT metabolism, especially L. rhamnosus.

Depression Can Be Transmitted via Gut Microbiota and Induce Liver Metabolic Disorders and Brain Inflammation

Background: Generally, depression is caused by a deficiency in the monoamine transmitters of the brain, norepinephrine (NE) and serotonin (5-HT). Recent studies have showed that the gut microbiota can affect brain function through the microbiota-gut-brain axis. However, the underlying mechanism of the microbiota and potential influence of depression remain elusive. We aimed to determine how gut microbiota contribute to the process of depression and further influence of the host Methods: Fecal microbiota transplant (FMT) is applied to illustrate depression can be transmitted via microbiota and metabolism and serum analysis are applied to demonstrate further influence to the liver and the brain. Findings: Depression-like behavior is observed after antibiotic-treated rats colonize gut microbiota derived from chronic unpredictable mild stress (CUMS) rats, which corresponds to a decrease in 5-HT expression in plasma. Moreover, increased Zonulin and Fatty Acid Binding Protein-2 (FABP2) in the plasma indicate that gut barrier integrity is broken in FMT rats. Since the liver receives blood from the intestines and metabolizes the products of the gut microbiota, liver metabolic disorder occurs after FMT. LC-MS shows that changed metabolites were mainly assigned to 'energy metabolism', 'lipid metabolism' and 'acid metabolism' categories. In addition, increased inflammatory cytokines expression and higher astrocytes activation in the hippocampus indicating inflammatory process in the brain after FMT. Interpretation: These findings suggest that disturbance of the gut microbiota contribute to pathogenesis of depression and further cause liver metabolic disorders and brain inflammation. Funding Statement: This work was supported by the National Natural Science Foundation of China (NO. 31472232) and the Department of Agriculture of Guangdong Province, the Project of SCAU TCVM Training Base. Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: The study was approved by the Southern Medical University Experimental Animal Ethics Committee. All experimental procedures were performed in accordance with the relevant guidelines approved by the Experimental Animal Ethics Committee of Southern Medical University.

Exploring the potential role of sonic hedgehog cell signalling pathway in antidepressant effects of nicotine in chronic unpredictable mild stress rat model

Nicotine is the most common and highly addictive drug of abuse, associated with several life-threatening diseases and high mortality. Nicotine abuse is the concerted effort to feel reward and fight depression in depressed individuals. The underlying mechanism of nicotine is to activate the brain reward system in the central nervous system and provide an antidepressant effect. Antidepressants provide their therapeutic effect by stimulating hippocampal neurogenesis, which can be correlated with brain derived neurotrophic factor (BDNF) expression in the hippocampus. BDNF interacts with Wnt/β-catenin and sonic hedgehog (Shh) signalling cascade to stimulate hippocampal neurogenesis. Shh is the marker of hippocampal neurogenesis and also involved in the neuropathology of depression. But knowledge in this area to identify the potential therapeutic target is limited. In our study, we explored the role of BDNF, Wnt/β-catenin and Shh signalling in depression and the involvement of these signalling pathways in providing an antidepressant effect by nicotine. Our investigations showed that chronic unpredictable mild stress induced depression results declined expression of BDNF, Wnt/β-catenin, Shh and its downstream transcription factors GLI1/2/3 and NKX2.2 in the hippocampus of male Wistar rat. Moreover, we also observed that nicotine administration increased the expression of these signalling molecules in providing the antidepressant effects.

Pharmacokinetics-pharmacodynamics and tissue distribution analysis of Low Polar extract of Xiaoyao Powder combined with rat model of chronic unpredictable mild stress

Xiaoyao powder (XYP) is a valuable traditional Chinese Medicine (TCM) prescription developed for depression. Previous findings have suggested that the low polar extract of XYP (XYP-A) was more effect than other parts and its main ingredients included ligustilide, (2Z,8Z,10E)-pentadecatriene-4,6-diyn-1-ol (RB-1), (2Z,8E,10E)-pentadecatriene-4,6-diyn-1-ol (RB-2), (2Z,8Z,10E)-heptadecatriene-4,6-diyn-1-ol (RB-3), and bupleurynol (RB-4). However, the correlation between concentration of main ingredients and effects is still indeterminate. This study developed an ultra performance lipid chromatography combined with photo-diode array detector (UPLC-PDA) method to determine the contents of main ingredients in serum and tissues for pharmacokinetics and tissue distribution analysis. And, norepinephrine (NE) and 5-hydroxytryptamine (5-HT) were selected as the pharmacodynamic index and determined using the method of high performance lipid chromatography combined with fluorescence detector (HPLC-FD) in the serum for pharmacodynamics analysis. The DAS3.0 software was used to fit the pharmacokinetics-pharmacodynamics (PK-PD) model. The pharmacokinetic assay revealed that the absorption of polyacetylene compound was more favorable under pathological status. And, the result of tissue distribution showed that RB-2 and RB-4 were rapidly and widely distributed in tissues, and easy to cross the blood-brain barrier. The comparison of the value of NE and 5-HT in chronic unpredictable mild stress (CUMS) and control group rats suggested that 5-HT might be the main targets for the four polyacetylene compounds. The present study demonstrated that XYP-A showed the certain therapeutic effect of for depression safely and that polyacetylene compounds might be active ingredient for depression.

N-acetylcysteine attenuates neuroinflammation associated depressive behavior induced by chronic unpredictable mild stress in rat.

Depression is a heterogeneous disorder and associated with inflammatory responses. The influences of N-acetylcysteine (NAC) on neuroinflammation associated depression-like behavior have not been investigated yet, and associated biochemical changes are currently unclear. Therefore, we assessed the effects of NAC on neuroinflammation associated depression-like behavior induced through chronic unpredictable mild stress (CUMS) in rats. The antidepressant-like effect of NAC was depicted using the sucrose preference test and the forced swimming test (FST) while CUMS-induced alteration in the locomotor index was measured using the open field test (OFT) and actophotometer. Our results revealed that CUMS exposure markedly aggravated depression-like behavior, the levels of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, and reduced the serotonin levels. One-week consecutive NAC (50 and 100 mg/kg, p.o.) or fluoxetine (10 mg/kg, p.o., a selective serotonin reuptake inhibitor) treatment significantly increased sucrose preference index, reduced immobility time in the FST, and the increased the number of squares crossed, number of rearing in the OFT and locomotion in the actophotometer in the CUMS-exposed rats. Moreover, the levels of pro-inflammatory cytokines in the hippocampus as well as pre-frontal cortex were suppressed, and remarkably restored the serotonin levels by NAC (50 and 100 mg/kg, p.o.) or fluoxetine (10 mg/kg, p.o.) administration. However, NAC (25 mg/kg, p.o.) exerted insignificant protection against CUMS-induced depressive-like behavior and associated neuro-inflammation. This study demonstrates that NAC exhibited the antidepressant-like effect in the CUMS-exposed rats, which might be mediated by anti-inflammatory potential and restoring serotonergic responses in the stressed rats.

Minocycline ameliorates anxiety-related self-grooming behaviors and alters hippocampal neuroinflammation, GABA and serum cholesterol levels in female Sprague-Dawley rats subjected to chronic unpredictable mild stress

Neuroinflammation induced by stress results in aberrant neurotransmission and dyslipidemia, which can trigger depression- and anxiety-like behaviors. Gamma-aminobutyric acid (GABA) and cholesterol play a crucial role in anxiety-like states, including self-grooming - a common stress-evoked rodent behavior. However, the interaction between neuroinflammation, GABA and cholesterol under stress, and their effects on grooming, remain unclear. Here, we utilize the chronic unpredictable mild stress (CUMS) rat cohort used previously in our Zhang et al. (2019) study, to examine whether CUMS affects grooming behavior, and whether minocycline, a microglia antagonist, can correct these behavioral deficits, accompanied by altering hippocampal neuroinflammation, GABA and serum cholesterol levels. Female Sprague-Dawley rats underwent a 6-week CUMS and received daily minocycline (40 mg/kg, i.p.) during this period, followed by behavioral testing in the open field test. Serum cholesterol, inflammatory cytokines and GABA levels in hippocampus were assayed by ELISA. CUMS significantly decreased locomotion, rearing, central zone entries and time spent in the open field center compared to unstressed controls. CUMS also strongly affected self-grooming behaviors, increasing the frequency of grooming episodes, the number of transitions, interruptions and individual elements of various grooming phases. However, these CUMS-induced behavioral abnormalities were corrected by minocycline. Likewise, CUMS elevated total serum cholesterol and lowered serum high-density lipoprotein cholesterol, whereas minocycline ameliorated these responses. CUMS also lowered hippocampal GABA, whereas minocycline normalized CUMS-induced GABA in the hippocampus. We also found significant correlations between neuroinflammation and GABA, neuroinflammation and cholesterol, GABA and grooming, as well as cholesterol and grooming measures, further implicating stress-evoked neuroinflammation, GABA and cholesterol in the regulation of complex rodent behaviors. In summary, minocycline ameliorated CUMS-induced aberrant self-grooming behaviors in rats by altering hippocampal neuroinflammation, GABA and serum cholesterol levels.

Impact of traditional Chinese medicine treatment on chronic unpredictable mild stress-induced depression-like behaviors: intestinal microbiota and gut microbiome function.

Gut microbiota dysbiosis is a recognized contributing factor to many noncommunicable diseases, but more evidence is still needed to illustrate its causative impact on mental and brain health disorders and mechanism(s) for targeted mitigation. Traditional Chinese Medicine (TCM) has been used in the management of neuropsychiatric diseases for many years in China. In this study, a randomized, controlled trial was conducted to examine the impact of stress on gut microbiota dysbiosis and depression, and TCM in alleviating the damage using Chronic Unpredictable Mild Stress (CUMS) rats, a well-established rodent model for depression. The behaviors of rats and the profiles of the fecal microbiota were assessed by an array of behavioral tests and 16S rRNA gene sequencing, and the intestinal microbial function was assessed by shotgun sequencing-based metagenomic analysis of microbial DNA from fecal samples. Data on brain targeted metabolites by liquid chromatography-mass spectrometry (LC-MS) were also discussed. Depressive and anxiety-like behaviors and changes in the fecal microbiota profile were observed in CUMS rats, which were then significantly reversed in CUMS rats that received TCM. Specifically, TCM treatment reduced the levels of Firmicutes, and Ruminococcus, and increased the abundance of Bacteroidetes and Roseburia, reportedly being associated with relieving psychiatric disorders. Furthermore, the levels of brain metabolites perturbed by CUMS were reversed by TCM treatment, and Spearman's correlation analysis illustrated strong correlation between brain metabolites and perturbed fecal microbiota genera. Finally, the fecal microbiome of CUMS rats was characterized by alterations in amino acid metabolism and evaluation of bile acid biosynthesis, and TCM-treated rats showed elevation of cysteine and methionine metabolism. Overall, these results indicated that administration of the TCM may mitigate CUMS-induced depression-behaviors, and it is correlated with reversing CUMS-induced intestinal microbiota dysbiosis; evidence also supported related changes in brain metabolites. These findings set up the foundation to further reveal the exact causal relationship among the TCM formula, host responses, gut microbiota dysbiosis and the levels of brain metabolites, and enabled scientific interpretation of the therapeutic function of the TCM.

L-theanine ameliorate depressive-like behavior in a chronic unpredictable mild stress rat model via modulating the monoamine levels in limbic-cortical-striatal-pallidal-thalamic-circuit related brain regions.

L-theanine, originally found in green tea, elicits various physiological effects, such as promoting relaxation, improving concentration and learning ability, and providing antianxiety-like and antidepressant-like properties. This study aims to investigate the effects of L-theanine (2mg/kg) on monoamine levels in an animal model of depression. The effect of l-theanine on the symptoms of depression was examined through the open-field test, sucrose preference test, and forced swim test. The monoamine neurotransmitters that involve serotonin (5-HT), norepinephrine (NE), and dopamine (DA) were measured in the limbic-cortical-striatal-pallidal-thalamic (LCSPT)-circuit related brain regions, including the prefrontal cortex (PFC), nucleus accumbens (NAC), striatum (ST), amygdala, and hippocampus (HIP). L-theanine ameliorated the depressive-like behaviors in the chronic unpredictable mild stress (CUMS) rat model. In the PFC, NAC, and HIP, L-theanine administration significantly increased the levels of 5-HT, NE, and DA. In the ST, the levels of 5-HT and DA were increased after the administration of L-theanine. However, in the HIP, only the level of DA significantly changed after the treatment of L-theanine. Taken together, these results indicated that L-theanine has possibly antidepressant-like effects in the CUMS rat model, which could be mediated by the monoamine neurotransmitters in the LCSPT-circuit related brain regions.

Protective effect of Convolvulus pluricaulis against neuroinflammation associated depressive behavior induced by chronic unpredictable mild stress in rat

Depression is a heterogeneous disorder and has been regarded as an inflammatory disease. The aerial parts of the Convolvulus pluricaulis are used in Indian traditional medicines for the management of nervous disorders. However, the influence of methanolic extract of aerial parts of Convolvulus pluricaulis (CPE) on a chronic animal model of depression has not been investigated yet, and associated biochemical changes are still unclear. Therefore, this study investigates the effects of CPE on a chronic rat model of depression and explores its underlying mechanism of action on neuroinflammation and brain monoamines. The antidepressant-like effect of CPE (25, 50, and 100 mg/kg, p.o.) was depicted using the sucrose preference test and the forced swimming test (FST) while CUMS-induced alteration in the locomotor index was measured using the open field test (OFT) and actophotometer. A consecutive one-week treatment of CPE (50, and 100 mg/kg) or fluoxetine (10 mg/kg, p.o.) treatment significantly increased sucrose preference index, reduced immobility time in the FST, and increased the number of squares crossed, the number of rearing in the OFT and locomotion in the actophotometer in the CUMS-exposed rats. Moreover, elevated levels of pro-inflammatory cytokines IL-1β, IL-6, TNF-α and liver biomarkers ALT, AST were also significantly reversed by CPE (50, and 100 mg/kg) or fluoxetine administration in the CUMS-exposed rats. Furthermore, a one-week treatment of CPE (50 and 100 mg/kg) or fluoxetine also remarkably restored the serotonin and noradrenaline levels in the hippocampus as well as in the prefrontal cortex of the CUMS-exposed rats. However, CPE (25 mg/kg) exerted insignificant protection against CUMS-induced depressive-like behavior and associated neuroinflammation. Therefore, this study demonstrates that CPE exerted antidepressant-like effect which could be mediated by anti-inflammatory potential, restoring liver biomarkers or monoaminergic responses in the stressed rats.

ITRAQ-Based Quantitative Proteomics Suggests Synaptic Mitochondrial Dysfunction in the Hippocampus of Rats Susceptible to Chronic Mild Stress.

Mounting studies show that hippocampal synaptic transmission and plasticity are abnormal in depression. It has been suggested that impairment of synaptic mitochondrial functions potentially occurs in the hippocampus. Thus, the synaptic mitochondria may be a crucial therapeutic target in the course of depression. Here, we investigated the potential dysregulation of synaptic mitochondrial proteins in the hippocampus of a chronic mild stress (CMS) rat model. Proteomic changes of hippocampal synaptosomes containing synaptic mitochondria were quantitatively examined using the isobaric tag for relative and absolute quantitation labeling combined with tandem mass spectrometry. 45 Proteins were identified to be differentially expressed, of which 21 were found to be putative synaptic mitochondrial proteins based on gene ontology component and SynaptomeDB analyses. Detailed investigations of protein functions and disease relevance support the importance of hippocampal synaptic mitochondria as a key substrate contributing to impairment in synaptic plasticity of stress-related disorders. Interestingly, eight synaptic mitochondrial proteins were specifically associated to the susceptible group, and might represent part of molecular basis of depression. Further analysis indicated that the synaptic mitochondrial oxidative phosphorylation (OXPHOS) system was heavily affected by CMS in the susceptible rats. The present results provide novel insights into the disease mechanism underlying the abnormal OXPHOS that is responsible for energy-demanding synaptic plasticity, and thereby increase our understanding of the role of hippocampal synaptic mitochondrial dysfunction in depression.

Depression induced by chronic stress leads to penile cavernosal dysfunction: protective effect of anti-TNF-α treatment.

Psychological stress may lead to erectile dysfunction (ED), and inflammation has been evaluated as a major contributing factor. The goal of this study was to investigate the effects of etanercept (ETN), an anti-tumor necrosis factor α (TNF-α) protein, on cavernosal function in the unpredictable chronic mild stress (UCMS) rat model of depression. Animals were divided into 4 groups: animals not exposed to UCMS, animals not exposed to UCMS and treated with ETN, animals exposed to UCMS, and animals treated with ETN while exposed to UCMS. UCMS significantly impaired the neurogenic and endothelium-dependent relaxation responses; reduced cavernosal endothelial nitric oxide (NO) synthase (eNOS) and neuronal NO synthase (nNOS) expressions; decreased testosterone levels; enhanced systemic levels of corticosterone, TNF-α, interleukin 1β (IL-1β), interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule 1 (ICAM-1); and also increased cavernosal levels of TNF-α, IL-1β, and IL-6 in rats. ETN administration restored NO-mediated neurogenic and endothelium-dependent relaxation responses of the corpus cavernosum, increased cavernosal eNOS and nNOS expressions, enhanced testosterone levels, and decreased corticosterone levels in UCMS-exposed rats. Also, systemic inflammatory markers and cavernosal proinflammatory cytokine levels were reduced by ETN. Our results demonstrate the role of TNF-α-mediated inflammation in the development of depression and ED in rats exposed to chronic stress.

Role of Sitagliptin and Linagliptin in Amelioration of Chronic Mild Stress in Rats

Role of Sitagliptin and Linagliptin in Amelioration of Chronic Mild Stress in Rats

Monoaminergic and aminoacidergic receptors are involved in the antidepressant-like effect of ginsenoside Rb1 in mouse hippocampus (CA3) and prefrontal cortex

Ginsenoside Rb1 (Rb1), as the major bioactive ingredient of Panax ginseng C.A. Meyer, elicited a novel antidepressant-like effect in the forced swim test (FST) in chronic unpredictable mild stress (CUMS) rats in our previous study. To further explore the molecular mechanism of Rb1 on the neurotransmitters such as 5-hydroxytryptamine (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), norepinephrine (NE), dopamine (DA), homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), glutamate (Glu) and gamma-aminobutyric acid (GABA) in this antidepressant-like effect, the neurochemical changes in the monoaminergic and aminoacidergic receptors were investigated in the present pharmacological study by using reuptake inhibitors, receptors agonists and antagonists. The results showed that a sub-effective dose of Rb1 (5 mg/kg, p.o.) co-administered with fluoxetine (1 mg/kg, i.p., a selective serotonin reuptake inhibitor), reboxetine (2.5 mg/kg, i.p., a noradrenalin reuptake inhibitor), bupropion (10 mg/kg, i.p., a dopaminergic reuptake inhibitor), Mk-801 (0.05 mg/kg, i.p., an N-methyl-d-aspartic acid (NMDA) receptor antagonist) or baclofen (0.1 mg/kg, i.p., a selective GABA agonist) significantly decreased the immobility time in the FST. In addition, pretreating mice with NAN190 (0.5 mg/kg, i.p., a 5-HT1A receptor antagonist), ketanserin (5 mg/kg, i.p., a 5-HT2A/2C receptor antagonist), ondansetron (1 mg/kg, i.p., a 5-HT3A receptor antagonist), prazosin (1 mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α2-adrenoceptor antagonist), SCH23390 (0.05 mg/kg, i.p., a selective D1 receptor antagonist), haloperidol (0.2 mg/kg, i.p., a non-selective D2 receptor antagonist), NMDA (75 mg/kg, i.p., an agonist at the glutamate site) or bicuculline (4 mg/kg, i.p., a competitive GABA antagonist) reversed the antidepressant-like effect of Rb1 (10 mg/kg, p.o.) in the FST. The results obtained for the neurotransmitters in the mouse hippocampus (CA3) and prefrontal cortex showed that Rb1 up-regulated the levels of 5-HT, 5-HIAA, NE, DA, and GABA and decreased the level of Glu. However, there were no significant differences in HVA or DOPAC. Furthermore, there were no significant alterations in the total path of spontaneous locomotor activity in all treatments. These results suggest that both monoaminergic (serotonergic, noradrenergic and dopaminergic) and aminoacidergic (glutamatergic and GABAergic) receptors may be involved in the antidepressant-like effect of Rb1.

Novel antidepressant effects of Paeonol alleviate neuronal injury with concomitant alterations in BDNF, Rac1 and RhoA levels in chronic unpredictable mild stress rats.

Increasing evidence has suggested that major depressive disorder (MDD) is highly associated with brain-derived neurotrophic factor (BDNF) levels, dendrites atrophy, and loss of dendritic spines, especially in emotion-associated brain regions including the hippocampus. Paeonol is a kind of polyphenols natural product with a variety of therapeutic effects. Recent studies have reported its antidepressant effects. However, it is unclear what signaling pathways contribute to improve MDD. The present study investigated the effect of Paeonol on hippocampal neuronal morphology and its possible signaling pathways in chronic unpredictable mild stress (CUMS) rat model. Using CUMS rat model, the antidepressant-like effect of Paeonol was validated via depression-related behavioral tests. Neuronal morphology in hippocampal CA1 and DG was assessed using ImageJ's Sholl plugin and RESCONSTRUCT software. BDNF signaling pathway-related molecules was determined by Western blotting. Paeonol attenuated CUMS-induced depression-like behaviors, which were accompanied by hippocampal neuronal morphological alterations. After Paeonol treatment for 4weeks, the dendritic length and complexity and the density of dendritic spines markedly increased in the hippocampal CA1 and the dentate gyrus (DG). However, CUMS or Paeonol treatment does not selectively affect dendritic spine types. Simultaneously, administration of Paeonol deterred CUMS-induced cofilin1 activation that is essential for remolding of dendritic spines. The induction of CUMS downregulated BDNF levels and upregulated Rac1/RhoA levels; however, the tendency of these was inhibited by treatment with Paeonol. Our data suggest that BDNF-Rac1/RhoA pathway may be involved in attenuation of CUMS-induced behavioral and neuronal damage by Paeonol that may represent a novel therapeutic agent for depression.

Effects of Voluntary Wheel Running Exercise on the Depressive-Like Behavior and Circadian Alterations of Neuroendocrine Induced by Chronic Unpredictable Mild Stress in Rats

Effects of Voluntary Wheel Running Exercise on the Depressive-Like Behavior and Circadian Alterations of Neuroendocrine Induced by Chronic Unpredictable Mild Stress in Rats