Chronic Unpredictable Mild Stress Model Research Articles

Methane-rich saline ameliorates depressive-like behaviors during chronic unpredictable mild stress (CUMS).

Depression, considered the most prevalent neuropsychiatric disorder, is multifactorial and complex. Oxidative stress and inflammation significantly contribute to its etiology. Conversely, methane, a novel therapeutic gas, has demonstrated efficacy in enhancing tissue resilience against ischemic injuries and inflammation. In this study, we investigated the effect of methane-rich saline (MRS) on depression using the chronic unpredictable mild stress (CUMS) model. Depressed rats received MRS treatment, and depression-like behaviors and cognitive function were assessed through sucrose preference, open field, forced swimming, and Morris water maze tests. Additionally, we measured serum corticosterone levels, antioxidant enzyme activity, hippocampal malondialdehyde (MDA), and TNFα levels, and investigated histological changes in the hippocampus. Our findings revealed that MRS significantly ameliorated Depressive-like behaviors and cognitive impairment. Furthermore, MRS administration regulated serum corticosterone levels and also MRS reduced hippocampal lipid peroxidation, TNFα, and hippocampus tissue damage. MRS likely exerts its effects by reducing oxidative stress and inflammatory factors and modulating the function of the hypothalamus-pituitary-adrenal (HPA) axis. These results demonstrate the protective effects of MRS on the hippocampus in CUMS animals.

Hippocampal SorCS2 overexpression represses chronic stress-induced depressive-like behaviors by promoting the BDNF-TrkB system

BackgroundEmerging data has demonstrated that in mature neurons, SorCS2 localizes to the postsynaptic density of dendritic spines and facilitates plasma membrane sorting of TrkB by interacting with it, transmitting positive signaling from BDNF on neurons. Thus, it is possible that SorCS2 plays a role in the pathophysiology of depression by regulating the BDNF-TrkB system. MethodsIn the present study, SorCS2 expression in different brain regions [hippocampus, medial prefrontal cortex (mPFC), hypothalamus, amygdala, ventral tegmental area (VTA), and nucleus accumbens (NAc)] was thoroughly investigated in the chronic social defeat stress (CSDS) and chronic unpredictable mild stress (CUMS) models of depression. The changes in depressive-like behaviors, the hippocampal BDNF signaling cascade, and amounts of hippocampal immature neurons were further investigated after SorCS2 overexpression by microinjection of the adenovirus associated virus vector containing the coding sequence of mouse SorCS2 (AAV-SorCS2) into the hippocampus of mice exposed to CSDS or CUMS. ResultsIt was found that both CSDS and CUMS significantly decreased the protein and mRNA expression of SorCS2 in the hippocampus but not in other brain regions. Chronic stress also notably downregulated the level of hippocampal SorCS2-TrkB binding in mice. In contrast, AAV-based genetic overexpression of hippocampal SorCS2 fully reversed the chronic stress-induced not only depressive-like behaviors but also decreased SorCS2-TrkB binding, BDNF signaling pathway, and amounts of immature neurons in the hippocampus of mice. ConclusionAll these results suggest that enhancing the hippocampal SorCS2 expression protects against chronic stress, producing antidepressant-like actions. Hippocampal SorCS2 may participate in depression neurobiology and be a potential antidepressant target. Significance statementTargeting of proteins to distinct subcellular compartments is essential for neuronal activity and modulated by VPS10P domain receptors which include SorCS2. In mature neurons, SorCS2 localizes to the postsynaptic density of dendritic spines and facilitates plasma membrane sorting of TrkB by interacting with it, transmitting positive signaling from BDNF on neurons. Our study is the first direct evidence preliminarily showing that SorCS2 plays a role in depression neurobiology. It was found that chronic stress induced not only depressive-like behaviors but also decreased SorCS2 expression in the hippocampus. Chronic stress did not affect SorCS2 expression in the mPFC, hypothalamus, amygdala, VTA, or NAc. In contrast, genetic overexpression of hippocampal SorCS2 prevented against chronic stress, producing antidepressant-like actions in mice. Thus, hippocampal SorCS2 is a potential participant underlying depression neurobiology and may be a novel antidepressant target. Our study may also extend the knowledge of the neurotrophic hypothesis of depression.

Network Pharmacology and Transcriptomics to Explore the Pharmacological Mechanisms of 20(S)-Protopanaxatriol in the Treatment of Depression.

Depression is one of the most common psychological disorders nowadays. Studies have shown that 20(S)-protopanaxatriol (PPT) can effectively improve depressive symptoms in mice. However, its mechanism needs to be further explored. In this study, we used an integrated approach combining network pharmacology and transcriptomics to explore the potential mechanisms of PPT for depression. First, the potential targets and pathways of PPT treatment of depression were screened through network pharmacology. Secondly, the BMKCloud platform was used to obtain brain tissue transcription data of chronic unpredictable mild stress (CUMS) model mice and screen PPT-altered differential expression genes (DEGs). Gene ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed using network pharmacology and transcriptomics. Finally, the above results were verified by molecular docking, Western blotting, and quantitative real-time polymerase chain reaction (qRT-PCR). In this study, we demonstrated that PPT improved depression-like behavior and brain histopathological changes in CUMS mice, downregulated nitric oxide (NO) and interleukin-6 (IL-6) levels, and elevated serum levels of 5-hydroxytryptamine (5-HT) and brain-derived neurotrophic factor (BDNF) after PPT treatment compared to the CUMS group. Eighty-seven potential targets and 350 DEGs were identified by network pharmacology and transcriptomics. Comprehensive analysis showed that transthyretin (TTR), klotho (KL), FOS, and the phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) signaling pathway were closely associated with the therapeutic effects of PPT. Molecular docking results showed that PPT had a high affinity for PI3K, AKT, TTR, KL, and FOS targets. Gene and protein level results showed that PPT could increase the expression of PI3K, phosphorylation of PI3K (p-PI3K), AKT, phosphorylation of AKT (p-AKT), TTR, and KL and inhibit the expression level of FOS in the brain tissue of depressed mice. Our data suggest that PPT may achieve the treatment of depression by inhibiting the expression of FOS, enhancing the expression of TTR and KL, and modulating the PI3K-AKT signaling pathway.

Nanoliposomal in situ gel of fluoxetine and embelin as a potent intervention for depression via the intranasal route in CUMS animal model

Due to the intricate mechanism of depression, slow therapeutic effect, and intolerable side effects, fluoxetine does not treat its many symptoms. To address monotherapy's limitations, novel and synergistic therapies are needed. This study delves into the potential of thermosensitive nanoliposomal gel loaded with fluoxetine and embelin (FXT-EMB NLs in situ gel) to manage depression via the intranasal route in a chronic unpredictable mild stress (CUMS) animal model. FXT-EMB NLs were prepared using thin-film hydration, optimized by a central composite design, and loaded into an in situ gel containing Poloxamer-407 and HPMC polymers. The optimized NLs had satisfactory vesicle size (92.6 ± 1.3 nm), TEM, SEM, PDI (0.22 ± 0.01), zeta potential (35.1 ± 0.2 mV), and entrapment efficiency (87.09 and 73.26 % for FXT and EMB) results. DSC, FTIR, and XRD confirmed the purity of APIs, compatibility, and loading efficiency of the in situ gel. The in vitro release showed sustained release, whereas the ex vivo permeation and CLSM studies demonstrated enhanced permeation across goat nasal mucosa (19.351 and 19.6 μg/cm2/h). DPPH assay confirmed the antioxidant potential of the NLs and was non-irritant according to the nasal toxicity and HET-CAM studies. The N2a neuroblastoma cell line revealed cell viability and the synergistic effect of the drug combination (CI < 1). The in vivo study found that NLs significantly enhanced SOD and CAT levels in Wistar rats, and reduced IL-6, TNF-α levels, and immobility time in the CUMS model of depression (p < 0.001). The combination and synergistic antioxidant action of FXT and EMB-loaded NLs in situ gel could be beneficial for effectively treating depression.

Light and classical music therapies attenuate chronic unpredictable mild stress-induced depression via BDNF signaling pathway in mice

Depression, a pervasive mental health issue, often necessitates innovative therapeutic interventions. This study explores the efficacy of music therapy, a non-pharmacological approach, in ameliorating depression symptoms in a murine model. Employing a chronic unpredictable mild stress (CUMS) model to induce depressionlike behaviors in mice, we investigated the therapeutic potential of four distinct music genres: light, classical, atonal composition, and rock music. Behavioral assessments, including sucrose preference and immobility time, were conducted to evaluate the impact of music therapy. Additionally, we measured the levels of brain-derived neurotrophic factor (BDNF), synaptic proteins and neurogenesis to elucidate the underlying biological mechanisms. Our findings indicated that light and classical music significantly alleviated depression-like behaviors in mice, evidenced by increased sucrose preference and reduced immobility time. Conversely, atonal composition and rock music did not yield similar therapeutic benefits. Biochemically, light and classical music were associated with decreased levels of corticosterone and increased levels of glucocorticoid receptor, alongside enhanced BDNF signaling, synaptic proteins and neurogenesis. In conclusion, the study demonstrates that specific genres of music, notably light and classical music, may contribute to alleviating depression-like symptoms, potentially through mechanisms associated with BDNF signaling and neurogenesis. These results highlight the potential of targeted music therapy as a complementary approach in treating depression, with implications for its incorporation into broader therapeutic regimes. Further re-search is warranted to translate these findings into clinical practice.

A classic prescription alleviates inflammation in CUMS model mice via modulating MYDGF/MAP4K4/NF-κB signaling pathway, verified through UPLC-HRMS and proteomics analysis

BackgroundXiaoyaosan (XYS), a renowned classical traditional Chinese medicinal formula utilized in addressing major depressive disorder (MDD), has garnered significant acclaim for its remarkable efficacy in clinical application. The onset of major depressive disorder (MDD) often correlates with chronic unpredictable mild stress (CUMS), a pivotal instigating factor in its development.Aim of the study: This study aims to clarify the potential anti-inflammatory mechanisms of XYS in treating CUMS model mice. Materials and methodsUtilizing cutting-edge ultra high-performance liquid chromatography - high-resolution mass spectrometry (UPLC-HRMS), the active constituents of XYS were discerned, while employing proteomics analysis to delve into the potential mechanisms of its efficacy. Molecular docking studies, alongside subsequent in vivo experiments utilizing CUMS model mice, were conducted to corroborate the findings derived from the proteomics analysis. ResultsIn vivo experiments demonstrated that XYS not only markedly ameliorated behavioral markers but also attenuated serum inflammatory markers and suppressed IL-6 and TNF-α expression within the brains of CUMS model mice. Proteomics analysis suggested that the pivotal anti-inflammatory mechanism of XYS against CUMS-induced damage might involve modulation of the MAPK signaling pathway. Utilizing UPLC-HRMS, the active constituents of XYS were successfully identified, while molecular docking investigations explored interactions between XYS and MYDGF, PKC, MAP4K4, P-p65, p65, P-IKBα, and IKBα. The findings revealed XYS's regulatory influence on the MYDGF/MAP4K4/NF-κB signaling cascade. ConclusionsThis study is the first to our knowledge to demonstrate that XYS can alleviate inflammation in CUMS model mice by modulating the MYDGF/MAP4K4/NF-κB signaling pathway.

Effect of saponins in Panax notoginseng (Burkill) F. H. Chen on the steroid hormone levels in the chronic unpredictable mild stress model of depression in rats

Recent research has indicated that Panax notoginseng saponins (PNS) extracted from the radix of Panax notoginseng (Burkill) F. H. Chen exert antidepressant effects. This study aimed to assess the antidepressive effects of ginsenoside Rg1 and PNS in a depression model induced by chronic unpredictable mild stress (CUMS). Over a period of three weeks, rats were administered ginsenoside Rg1 at a dose of 30 mg/kg and PNS at dosages ranging from 100 to 200 mg/kg body weight per day. To assess how ginsenoside Rg1 and PNS influence depression-like behaviours in rats, various assessments were conducted, including coat state evaluation, forced swim test, and elevated plus maze test. The levels of cortisol and testosterone in serum samples were analysed using the liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) method. LC-ESI-MS/MS method provides precise and accurate results. The lower limit of quantification values for cortisol and testosterone were determined as 100 and 2 pg/mL, respectively. Our data demonstrated that both ginsenoside Rg1 and PNS significantly reversed depression-like behaviour in rats by improving coat condition, reducing immobility time in the forced swim test, and increasing time spent in the open arms of the elevated plus maze test. Furthermore, ginsenoside Rg1 and PNS exhibited a regulatory effect on cortisol and testosterone levels in plasma. These findings suggest that ginsenoside Rg1 and PNS may be potential antidepressants in clinical treatment.

Saikosaponin antidepressant mechanism: Improving the sphingolipid metabolism in the cortex via Apolipoprotein E and triggering neurovascular coupling

BackgroundSince the pathogenesis of depression is complex, antidepressant therapy remains unsatisfactory. Recent evidence suggests a link between depression and lipid metabolism. Saikosaponin (SS) exhibits antidepression and lipid-regulating effects in modern pharmacology. However, it is unknown whether lipid regulation is the key mechanism of the SS antidepressant effect and how it works. PurposeIn this study, we investigated the relationship between the antidepressant activity of SS and the regulation of lipid metabolism and explored potential mechanisms. MethodsAPOE-/- mice, in combination with the chronic unpredictable mild stress (CUMS) model, were used to study the relationship between SS antidepressant activity and lipid metabolism through behavioral, electrophysiological techniques, and non-targeted lipidomics. Western blot, primary cell culture technology, and laser speckle cerebral blood flow imaging were employed to elucidate potential mechanisms. GraphPad Prism was used for statistical analysis, and p < 0.05 was considered statistically significant. ResultsAPOE-/- mice exhibit more severe depressive-like behavior and dysregulation of sphingolipid metabolism in CUMS. SS alleviates depressive behavior and cortical sphingolipid metabolism disorder caused by CUMS, but has no effect on APOE-/- mice. SS alleviates the imbalance between ceramide (Cer) and sphingomyelin (SM) through acidic sphingomyelinase (AMSase). In addition, SS regulates neuronal glutamate release via sphingolipid metabolism, thereby alleviating the CUMS-induced inhibition of neurovascular coupling (regulates metabotropic glutamate receptor and IP3 receptor), which ameliorates the reduction of cerebral blood flow in depressed mice. ConclusionOur study highlights the role of lipid metabolism in the antidepressant activity of SS and explores its underlying mechanisms. This study provided new insights into the better understanding of the antidepressant mechanisms of phytomedicine while increasing the possibility of lipid metabolism as a therapeutic strategy for depression.

Repetitive Transcranial Magnetic Stimulation Reversing Abnormal Brain Function in Mood Disorders with Early Life Stress: from preclinical models to clinical applications

BackgroundEarly life stress (ELS) significantly increases the risk of mood disorders and affects the neurodevelopment of the primary cortex. HypothesisModulating the primary cortex through neural intervention can ameliorate the impact of ELS on brain development and consequently alleviate its effects on mood disorders. MethodWe induced the chronic unpredictable mild stress (CUMS) model in adolescent rats, followed by applying repetitive transcranial magnetic stimulation (rTMS) to their primary cortex in early adulthood. To assess the applicability of primary cortex rTMS in humans, we recruited individuals aged 17–25 with mood disorders who had experienced ELS and performed primary cortex rTMS on them. Functional magnetic resonance imaging (fMRI) and depression-related behavioral and clinical symptoms were conducted in both rats and human subjects before and after the rTMS. ResultsIn animals, fMRI analysis revealed increased activation in the primary cortex of CUMS rats and decrease subcortical activation. Following the intervention of primary cortex rTMS, the abnormal functional activity was reversed. Similarly, in mood disorders patients with ELS, increased activation in the primary cortex and decreased activation in the frontal cortex were observed. During rTMS intervention, similar neuroimaging improvements were noted, particularly decreased activation in the primary cortex. This suggests that targeted rTMS in the primary cortex can reverse the abnormal neuroimaging. ConclusionThis cross-species translational study has identified the primary cortex as a key region in mood disorders patients with ELS. Targeting the primary cortex with rTMS can correct abnormal functional activity while improving symptoms. Our study provides translational evidence for therapeutics targeting the ELS factor of mood disorders patients.

Inflammation, Oxidative Stress, and Chronic Unpredictable Mild Stress Model of Depression

Depression is one of the most common psychiatric disorders. Animal models represent a valuable research tool to investigate the molecular pathogenic mechanisms of depression and to develop and test different possible antidepressant drugs. Therefore, several murine models have been established, but the chronic unpredictable mild stress model has robust evidence. Inflammation and oxidative stress pathways have a clear involvement in the complex and intricate pathophysiology of depression, with strong evidence coming from studies using the chronic unpredictable mild stress model. This review provides an overview of the characteristics of the chronic, unpredictable mild stress model of depression and its role in investigating inflammation and oxidative stress pathways in depression.

Feasibility of Using Serum, Plasma, and Platelet 5-hydroxytryptamine as Peripheral Biomarker for the Depression Diagnosis and Response Evaluation to Antidepressants: Animal Experimental Study.

Whether peripheral blood 5-hydroxytrptamine (5-HT) levels serve as biomarker for depression diagnosis/response evaluation has not been well determined. This work was explored to address this inconclusive issue. Animals were randomized into normal control group (NC, n = 10) and chronic unpredictable mild stress model group (CUMS-model, n = 20), respectively. Animals in CUMS-model group were subjected to chronic stress, then they were randomly subdivided into CUMS subgroup and CUMS + fluoxetine subgroup (CUMS + FLX). After FLX treatment, blood and tissues were collected. 5-HT and relevant protein expression were measured. In mice model, there was a significant increase in serum and a significant reduction in plasma 5-HT levels in CUMS-model group versus NC group, while platelet 5-HT levels change little. After FLX treatment, serum and platelet 5-HT levels were significantly decreased in CUMS + FLX subgroup, while plasma 5-HT levels had not much change versus CUMS subgroup. Chronic stress enhanced colon and platelet serotonin transporter (SERT) expression and FLX treatment mitigated SERT expression. In rats' model, there was a significant increase in serum 5-HT levels while plasma and platelet 5-HT levels showed little change in CUMS group versus NC group. After FLX treatment, serum, plasma and platelet 5-HT levels were significantly decreased in CUMS + FLX subgroup versus CUMS subgroup. The profile of relevant proteins expression changed by FLX were like those in mice. Serum 5-HT levels might serve as a potential biomarker for depression diagnosis, meanwhile serum and platelet 5-HT levels might respond to antidepressant treatment.

Du-moxibustion ameliorates depression-like behavior and neuroinflammation in chronic unpredictable mild stress-induced mice

BackgroundNeuroinflammation is involved in the advancement of depression. Du-moxibustion can treat depression. Here, we explored whether Du-moxibustion could alleviate neuroglia-associated neuro-inflammatory process in chronic unpredictable mild stress (CUMS) mice. MethodsC57BL/6J mice were distributed into five groups. Except for the CON group, other four groups underwent CUMS for four consecutive weeks, and Du-moxibustion was given simultaneously after modeling. Behavioral tests were then carried out. Additionally, Western blot was conducted to measure the relative expression levels of high-mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B (NF-κB). Immunofluorescence was employed to evaluate the positive cells of ionized calcium binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP). Furthermore, interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were analyzed using an ELISA assay. ResultsWe found that CUMS induced depression-like behaviors, such as reduced sucrose preference ratio, decreased locomotor and exploratory activity, decreased the time in open arms and prolonged immobility. Furthermore, versus the CON group, the expression of HMGB1, TLR4, MyD88, NF-κB, positive cells of Iba-1, IL-1β and TNF-α were increased but positive cells of GFAP were decreased in CUMS group. However, the detrimental effects were ameliorated by treatment with CUMS+FLU and CUMS+DM. LimitationsA shortage of this study is that only CUMS model of depression were used, while other depression model were not included. ConclusionsDu-moxibustion alleviates depression-like behaviors in CUMS mice mainly by reducing neuroinflammation, which offers novel insights into the potential treatment of depression.

Adaptogenic action of diosgenin againsts chronic unpredictable mild stress-induced neuroimmune dysfunction of HPA axis reverses psychiatric behavior in mice

BackgroundStressful life experiences are associated with neurobehavioral abnormalities, such as anxiogenic-related depression and cognitive decline. Reportedly, adaptogens are well known to modulate stress-related responses and promote resilience. ObjectiveThis study aimed to assess the potential mechanisms and adaptogenic properties of diosgenin (DG), a phytosteroidal sapogenin with neuroendocrine protective effects, in chronic unpredictable mild stress (CUMS)-induced anxiogenic-depression and cognitive deficits in mice. MethodsDuring the 21-day study, mice were divided into five groups, and were daily treated with 5% dimethyl sulfoxide (control and CUMS model), diosgenin (25 mg/kg and 50 mg/kg) or fluoxetine (10 mg/kg) orally, respectively, followed by 21-item CUMS paradigm exposure, except for the control group. Mice were examined for anxiety, depression and cognitive-like features using relevant neurobehavioral paradigms. Biomarkers of oxidative stress, nitrite level, pro-inflammatory cytokines (TNF-α, IL-6), acetylcholinesterase (AChE), glutamic acid decarboxylase (GAD), and monoamine oxidase-B (MAOB) were measured in the prefrontal cortex, striatum, and hippocampal regions of the brain. Also, adrenal hypertrophy, serum corticosterone and glucose levels as a measure of hypothalamic pituitary adrenal (HPA) axis involvement were examined. ResultsDG ameliorated CUMS-induced behavioral anomaly, as characterized by the increased duration of grooming bouts in the sucrose preference test; decreased duration of immobility in the tail suspension and forced swim tests; anxiolytic effects in the elevated-plus maze, hole-board, light/dark compartment tests, as well as cognitive impairments indexed by the Y-maze and object recognition tests were reversed by DG respectively. DG remarkably decreased adrenal hypertrophy and elevated serum levels of corticosterone and glucose in CUMS mice. ConclusionConclusively, DG exhibits antidepressant-like and anxiolytic-like actions with memory enhancement in the CUMS mouse model, and thus could serve as an alternative agent for the management of depression and anxiety associated with cognitive decline in clinical settings.

Electroacupuncture intervention alleviates depressive-like behaviors and regulates gut microbiome in a mouse model of depression

Electroacupuncture (EA) is a neuroregulatory therapy for depression. Nonetheless, the effects of EA on the gut microbiome in mice models of depression are not well established. Here, using a chronic unpredictable mild stress (CUMS) model in mice, we evaluated the antidepressant effects of EA and changes in gut microbiota with behavioral tests and 16S rRNA gene sequencing. The results found that EA increased the time spent in the center area of the open-field test and the percentage of sucrose preference and reduced the immobility time in the tail suspension test in CUMS-treated mice. Furthermore, the genus Lachnoclostridium, Ruminococcaceae_UCG-002 and Rikenellaceae_RC9_gut_group were enriched in the CUMS group, which was positively correlated with depressive-like behaviors. Whereas phylum Actinobacteria and genus Allobaculum, Bifidobacterium, Dubosiella, Rikenella and Ileibacterium were enriched in the EA and CUMS + EA groups, all of which were negatively correlated with depressive-like behaviors. This study characterizes gut microbiota under EA treatment and provides new insights into the association of anti-depressive-like effects of EA and gut microbiota.

Effects of autotaxin and lysophosphatidic acid deficiencies on depression-like behaviors in mice exposed to chronic unpredictable mild stress

The involvement of lipids in the mechanism of depression has triggered extensive discussions. Earlier studies have identified diminished levels of lysophosphatidic acid (LPA) and autotaxin (ATX) in individuals experiencing depression. However, the exact significance of this phenomenon in relation to depression remains inconclusive. This study seeks to explore the deeper implications of these observations. We assessed alterations in ATX and LPA in both the control group and the chronic unpredictable mild stress (CUMS) model group. Additionally, the impact of ATX adeno-associated virus (AAV-ATX) injection into the hippocampus was validated through behavioral tests in CUMS-exposed mice. Furthermore, we probed the effects of LPA on synapse-associated proteins both in HT22 cells and within the mouse hippocampus. The mechanisms underpinning the LPA-triggered shifts in protein expression were further scrutinized. Hippocampal tissues were augmented with ATX to assess its potential to alleviate depression-like behavior by modulating synaptic-related proteins. Our findings suggest that the decrement in ATX and LPA levels alters the expression of proteins associated with synaptic plasticity in vitro and in vivo, such as synapsin-I (SYN), synaptophysin (SYP), and brain-derived neurotrophic factor (BDNF). Moreover, we discerned a role for the ERK/CREB signaling pathway in mediating the effects of ATX and LPA. Importantly, strategic supplementation of ATX effectively mitigated depression-like behaviors. This study indicates that the ATX-LPA pathway may influence depression-like behaviors by modulating synaptic plasticity in the brains of CUMS-exposed mice. These insights augment our understanding of depression's potential pathogenic mechanism in the context of lipid metabolism and propose promising therapeutic strategies for ameliorating the disease.

Electroacupuncture regulates gut microbiota to reduce depressive-like behavior in rats.

Growing studies show that gut microbiota is closely associated with depression. Acupuncture treatment could regulate the gut microbiota of many diseases. Here, we aim to observe the effect of electroacupuncture (EA) on gut microbiota in rats that showed depressive-like behavior. The rats were randomly divided into normal group, chronic unpredictable mild stress model (CUMS) group, CUMS + electroacupuncture (EA) group, and CUMS + sham-electroacupuncture (Sham) group. The CUMS+EA rats were treated with EA stimulation at bilateral Zusanli (ST36) and Tianshu (ST25) acupoints for 2 weeks (0.7 mA, 2/100 Hz, 30 min/day). The rats in the sham EA group were treated with the same conditions without inserting needles and electrical stimulation. Behavioral tests were conducted by forced swimming test (FST), open field test (OFT), and sucrose preference test (SPT) to assess depression-like behavior in rats. The relative abundance of intestinal bacteria in rat feces was detected by 16S rRNA analysis. The expression of calcitonin-gene-related peptide (CGRP), vasoactive intestinal peptide (VIP), somatostatin (SST), and adrenocorticotropic hormone (ACTH) in serum was detected by ELISA kit, and VIP, CGRP, and SST in the colon were detected by qRT-PCR and Western blot. Chronic unpredictable mild stress model rats exhibited depressive-like behaviors and had differential abundance vs. control rats. CUMS significantly decreased the relative abundance of Bifidobacterium and Streptococcus at the genus level, CGRP in plasma (p < 0.05), and significantly increased the intestine propulsion rate, the mRNA and protein expression of VIP, SST, and mRNA in the colon, and ATCH in plasma (p < 0.05). EA rats with microbial profiles were distinct from CUMS rats. EA markedly reduced the depressive-like behaviors, significantly increased the intestine propulsion rate, the relative abundance of Bacteroidetes, Proteobacteria, and Actinobacteria at the phylum level, Bifidobacterium and Streptococcus at the genus level, and VIP and CGRP in plasma (p < 0.05), and significantly decreased Firmicutes, the ratio of Firmicutes to Bacteroidetes at the phylum level, ACTH and SST in plasma, and SST mRNA in the colon (p < 0.05). The antidepressant effect of EA at ST36 and ST25 is related to regulating intestinal flora and the neurotransmitter system. Our study suggests that EA contributes to the improvement of depression, and gut microbiota may be one of the mechanisms of EA effect.

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.

Comparative analysis of the nucleus accumbens transcriptional features in multiple depressive animal models

Chronic stress is deemed a significant clinical contributor to depression. The use of animal models of chronic stress can fully reveal the complex pathological mechanisms and their changing trends in the pathogenesis of depression, which is crucial for both disease prevention and therapy. It is also unknown how various forms of stress differ in their impact on animal physiology and behavior. The nucleus accumbens (NAc), an essential brain area for the pathophysiology of depression, and its underlying neural mechanisms remain unclear. Here, we systematically compared transcriptional signatures in the NAc of four chronic stress models in rats: chronic unpredictable mild stress (CUMS), chronic social defeat stress (CSDS), learned helplessness (LH), chronic restraint stress (CRS). The majority of differentially expressed genes (DEGs) were unique to a single depression model, while the rank-rank hypergeometric overlap analysis showed that the CSDS and CRS models had the greatest overlap, and the CRS and CUMS models had the least. Then, we performed pathway analysis of the differential genes and found that the neuroactive ligand-receptor interaction pathway was significantly enriched not only in the LH, CRS and CSDS stress models, but also significantly enriched in stress genes that were also altered in at least two stress models. Finally, we found three hub genes (Dcx, Tnc and Wdfy4) by constructing co-expression networks for stress genes.In summary, our research has the potential to offer fresh insights into the molecular mechanisms underlying depression induced by different types of stress, highlighting both their similarities and differences. It may provide valuable clues for understanding the pathogenesis of depression.

Terazosin produces an antidepressant-like effect in mice exposed to chronic unpredictable mild stress behavioral alteration

Terazosin is an α1-adrenergic receptor antagonist that can relax smooth muscle and is prescribed to treat benign prostatic hyperplasia and, rarely, hypertension. The present study investigated the antidepressant-like actions of terazosin (TZ) in mice. They were first subjected to chronic unpredictable mild stress (CUMS) and then the effects of TZ were assessed using the forced swimming test (FST) and tail suspension test (TST), sucrose preference test (SPT), actophotometer test (APT). The changes in the PGK1 levels, neurotransmitters, and proinflammatory cytokines levels after chronic stress and TZ treatment were examined. It was found that TZ exhibited an antidepressant-like effect in the FST, TST, SPT, and APT. It was effective in the CUMS model of depression. It was also found that TZ treatment reduced the levels of proinflammatory cytokines and elevated the neurotransmitter levels in mice. Results of this study suggest that TZ has antidepressant-like actions in mice models of CUMS induced depression.

Histone 3 Trimethylation Patterns are Associated with Resilience or Stress Susceptibility in a Rat Model of Major Depression Disorder.

Major Depressive Disorder (MDD) is a severe and multifactorial psychiatric condition. Evidence has shown that environmental factors, such as stress, significantly explain MDD pathophysiology. Studies have hypothesized that changes in histone methylation patterns are involved in impaired glutamatergic signaling. Based on this scenario, this study aims to investigate histone 3 involvement in depression susceptibility or resilience in MDD pathophysiology by investigating cellular and molecular parameters related to i) glutamatergic neurotransmission, ii) astrocytic functioning, and iii) neurogenesis. For this, we subjected male Wistar rats to the Chronic Unpredictable Mild Stress (CUMS) model of depression. We propose that by evaluating the sucrose consumption, open field, and object recognition test performance from animals submitted to CUMS, it is possible to predict with high specificity rats with susceptibility to depressive-like phenotype and resilient to the depressive-like phenotype. We also demonstrated, for the first time, that patterns of H3K4me3, H3K9me3, H3K27me3, and H3K36me3 trimethylation are strictly associated with the resilient or susceptible to depressive-like phenotype in a brain-region-specific manner. Additionally, susceptible animals have reduced DCx and GFAP and resilient animals present increase of AQP-4 immunoreactivity. Together, these results provide evidence that H3 trimethylations are related to the development of the resilient or susceptible to depressive-like phenotype, contributing to further advances in the pathophysiology of MDD and the discovery of mechanisms behind resilience.