Depressive-like Behavioral Changes Research Articles

Antidepressant-like effects of the leaf extract of Mallotus oppositifolius (Geiseler) Müll. Arg. (Euphorbiaceae) in the chronic unpredictable mild stress model: A role of the gut-brain axis

The gut microbiota has been posited as a target for the treatment of major depressive disorder. Herein, we investigated the effect of the hydroethanolic leaf extract of Mallotus oppositifolius (MOE) on the gut microbiota of mice and how this contributes to its known antidepressant-like effect. A 6-week chronic unpredictable mild stress (CUMS) procedure was employed in 7 groups of mice to induce depression. From the third week, oral MOE treatments (10, 30, 100 mg/kg) and two reference drugs, fluoxetine (12 mg/kg) and minocycline (40 mg/kg), known to affect the gut microbiota, were administered. The sixth and seventh groups were the vehicle stressed (VEH-S) and non-stressed groups (VEH-NS). Changes in depressive-like behaviors were assessed using sucrose preference test while the forced swimming test (FST) was used to assess sustained antidepressant-effect after treatment discontinuation. Moreover, changes in prefrontal cortex (PFC) and hippocampal serotonin (5-HT) levels were evaluated using enzyme-linked immunosorbent assay (ELISA). The effect of treatment on the profile of the gut microbiota of the groups was elucidated using 16S rRNA Oxford Nanopore sequencing. MOE and reference drugs reversed the depression-associated reduction in sucrose preference when compared to VEH-S. MOE (with peak effect at 30 mg/kg) reduced immobility while increasing swimming and climbing behaviors. MOE reversed CUMS-induced reduction of 5-HT concentration in PFC and hippocampus. The behavioral effects of MOE were associated with shifts in the gut microbiota of CUMS-exposed mice. The study has provided seminal evidence that MOE ameliorates CUMS-induced depressive symptoms by modulating gut microbiota and increasing brain 5-HT levels.

Vitamin D Mitigates Depression-related Disorders in an Animal Model of Depression: A Behavioral, Anatomopahtological, and Molecular Investigation, Implicating the Hippocampal BDNF Signaling Pathway

Background: Major depressive disorder represents a complicated mental disorder characterized by persistent feelings of unhappiness and loss of interest. More evidence suggests a high potential correlation between vitamin D deficiency and depression. However, the underlying mechanisms and the therapeutic potential of vitamin D supplementation are still not properly understood. The purpose of this research is to evaluate the effect of vitamin D supplementation on depressive behaviors using a rat model of depression and explore the potential mechanisms involved. Depression is a prevalent mental health disorder that significantly impacts the quality of life of individuals. Despite the availability of various treatment options, many patients still experience suboptimal outcomes, highlighting the need for further exploration of novel therapeutic approaches. In recent years, the importance of vitamin D in mental health, particularly in depression, has gained considerable attention. Methods: In this project, we propose to utilize an animal model of depressed rats to evaluate the effect of vitamin D supplementation on depressive behaviors. We employed a range of well-established behavioral tests to assess changes in depressive-like behaviors following vitamin D supplementation. Additionally, histopathological examinations of the hippocampal region, known to be involved in mood regulation, were performed to assess structural alterations and cellular changes associated with depression and vitamin D supplementation. Results: The findings demonstrate the therapeutic potential of vitamin D supplementation by improving neuronal reorganization and proliferation in the hippocampus, suggesting an interest in investigating other mechanisms of interaction. Conclusion: The findings of this research will provide valuable insight into the therapeutic potential of vitamin D in depression and shed light on the underlying mechanisms involved.

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.

Repeated Sulforaphane Treatment Reverses Depressive-like Behavior and Exerts Antioxidant Effects in the Olfactory Bulbectomy Model in Mice.

Growing evidence suggests that activators of nuclear factor erythroid-derived 2-like 2 (Nrf2), such as sulforaphane, may represent promising novel pharmacological targets for conditions related to oxidative stress, including depressive disorder. Therefore, we conducted a study to explore the behavioral and biochemical effects of repeated (14 days) sulforaphane (SFN) treatment in the olfactory bulbectomy (OB) animal model of depression. An open field test (OFT), splash test (ST), and spontaneous locomotor activity test (LA) were used to assess changes in depressive-like behavior and the potential antidepressant-like activity of SFN. The OB model induced hyperactivity in mice during the OFT and LA as well as a temporary loss of self-care and motivation in the ST. The repeated administration of SFN (10 mg/kg) effectively reversed these behavioral changes in OB mice across all tests. Additionally, a biochemical analysis revealed that SFN (10 mg/kg) increased the total antioxidant capacity in the frontal cortex and serum of the OB model. Furthermore, SFN (10 mg/kg) significantly enhanced superoxide dismutase activity in the serum of OB mice. Overall, the present study is the first to demonstrate the antidepressant-like effects of repeated SFN (10 mg/kg) treatment in the OB model and indicates that these benefits may be linked to improved oxidative status.

Ginsenoside Rb1 protects hippocampal neurons in depressed rats based on mitophagy-regulated astrocytic pyroptosis

BackgroundAstrocytes play a vital role in offering functional support for neurons, which are related to the pathogenic mechanism of depression. Ginsenoside Rb1 (GRb1) is demonstrated with antidepressant-like activities. PurposeWe aimed to investigate whether GRb1 can inhibit mitophagy-mediated astrocytic pyroptosis to protect neurons in depression. Study DesignModel rats were subjected to chronic unpredictable mild stress (CUMS) for determining the in vivo antidepressant activity of GRb1. MethodsThe mitophagy-mediated antipyroptosis role of GRb1 was assessed in lipopolysaccharide (LPS) + ATP-stimulated astrocytes. The mechanism by which GRb1 protects synaptic plasticity was investigated using hippocampal neurons incubated in an astrocyte medium. The rat depressive-like behaviors were determined through sucrose preference, forced swimming, and the open-field tests. Escitalopram was used in the anti-depression control of GRb1. Cyclosporin A (CsA), a mitophagy inhibitor, and interleukin (IL)-1β were used to reverse the role of GRb1 in mitophagy and pyroptosis, respectively. ResultsGRb1 inhibited LPS-induced inflammation and activation in the astrocytes and repressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Also, GRb1 repressed LPS + ATP-promoted astrocytic pyroptosis. During GRb1 treatment, the activation of mitophagy with a decrease in ROS was observed in LPS + ATPs-stimulated astrocytes. CsA enhanced GRb1-decreased ROS and promoted astrocytic pyroptosis. The GRb1-treated astrocyte medium suppressed neuron death and increased neuron viability and synaptic density. Escitalopram and GRb1 improved the depressive-like behaviors of the rats. GRb1 activated mitophagy and inhibited astrocytic activation and pyroptosis in rats with depression. It also reduced impairments in synaptic structures and increased synaptic density in depressive-like rats. IL-1β increased astrocytic pyroptosis and reversed GRb1-enhanced synaptic plasticity in the rats exposed to CUMS. There were no statistical changes in depressive-like behaviors between GRb1 and Escitalopram groups. ConclusionGRb1 modulates mitophagy and the NF-κB pathway to inhibit astrocytic pyroptosis, thereby maintaining neurological homeostasis by repressing inflammation and enhancing synaptic plasticity.

The role of the gut microbiota in depressive-like behavior induced by chlorpyrifos in mice

Chlorpyrifos (CPF) is associated with depression, cognitive dysfunction, and other neurological disorders. Increasing evidence has suggested that the gut microbiota plays a vital role in regulating the development of depression. However, it is unknown whether gut microbiota is associated with CPF-related depression. This study aimed to explore the effect of CPF on depressive-like behavior in mice and investigated the role of gut microbiota in this behavior. In our study, we selected fifty male C57BL/6 J mice for the model and subjected them to CPF poisoning by gavage for 14 days. The depressive-like behaviors of mice were assessed by the open field test (OFT), sucrose preference test (SPT), and forced swimming test (FST). Furthermore, we selected the high-dose group (CPF10) with obvious changes in depressive-like behaviors for the hippocampus and colon histopathological analysis, examined the changes in the gut microbiota by 16 S rRNA sequencing, screened the different microbiota among groups by linear discriminant analysis effect size (LEfSe), analyzed the correlation between intestinal bacteria and depression-like behavior indicators by Spearman analysis, and evaluated the predictive ability of different bacteria to CPF-induced depressive-like behavior using the receiver operator characteristic (ROC) curve. The results showed that CPF caused depressive-like behaviors with pathological changes in the hippocampus and colon. CPF induced changes in gut microbiota, including 49 differential bacteria. Among the top 10 abundant bacteria, Actinobacteria and Deferribacteres were increased, and Cyanobacteria, Patescibacteria and Verrucomicrobia were decreased at the phylum level. Muribaculum, Ruminococcaceae.UCG.014 and uncultured Bacteroides bacterium were decreased at the genus level. Correlation analysis demonstrated that 18 differentially abundant bacteria were correlated with CPF-induced depression. ROC curves revealed that Deferribacteres, Mucispirillum, Rikenella and GCA900066575 are potential biomarkers for depression caused by CPF. These findings will provide an experimental basis for the neurological health of the pesticide-exposed population.

Regulatory role of cytokines on etiology of depression in animal models: their biological mechanisms and clinical implication with physical exercise.

It has been known that chronic psychological or physical stress elicits depressive behaviors (learned helplessness, anhedonia, anxiety, etc.) and also activates to release proinflammatory cytokines in the brain. Especially, postmenopausal women under stress condition exacerbates neuroimmune systems and mood disorder. Repeated restraint stress in the ovariectomized female rats poses an immune challenge which was capable of inducing depressive-like behaviors, promoting exaggerated corticosterone responses and changing the proinflammatory cytokine expression such as interleukin (IL)-1β in the brain. Also, anti-inflammatory cytokines including IL-4 are known to regulate inflammation caused by immune response or stress challenge. Furthermore, some studies reported that physical activity can reduce stress hormones and improve personal immunity. Physical exercise has been shown to be associated with decreased symptoms of depression and anxiety, and with improved physical health, immunological function, and psychological well-being. This paper aims to discuss an overview of how stress shapes neuroimmune response and diverse roles of cytokines in animals models, acting on depressive-like behavioral changes; some beneficial aspects of exercise on stress-related disorders are addressed.

Time course and mechanistic analysis of human umbilical cord perivascular cell mitigation of lipopolysaccharide-induced systemic and neurological inflammation

Background aimsBecause of their potent immunomodulatory and anti-inflammatory properties, mesenchymal stromal cells are a major focus in the field of stem cell therapy. However, the precise mechanisms underlying this are not entirely understood. Human umbilical cord perivascular cells (HUCPVCs) are a promising cell therapy candidate. This study was designed to evaluate the time course and mechanisms by which HUCPVCs mitigate lipopolysaccharide (LPS)-induced systemic and neurological inflammation in immunocompetent mice. To explore the underlying mechanisms, the authors investigated the biodistribution and fate of HUCPVCs. MethodsMale C57BL/6 mice were randomly allocated to four groups: control, LPS, HUCPVCs or LPS + HUCPVCs. Quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and cytokine arrays were used to assess changes in pro-inflammatory mediators systemically and in the brain. Depressive-like behavioral changes were evaluated via a forced swim test. Quantum dot (qDot) labeling and immunohistochemistry were used to assess the biodistribution and fate of HUCPVCs and interactions with recipient innate immune cells. ResultsA single intravenously delivered dose of HUCPVCs significantly reduced the systemic inflammation induced by LPS within the first 24 h after administration. HUCPVC treatment abrogated the upregulated expression of pro-inflammatory genes in the hippocampus and cortex and attenuated depressive-like behavior induced by LPS treatment. Biodistribution analysis revealed that HUCPVC-derived qDots rapidly accumulated in the lungs and demonstrated limited in vivo persistence. Furthermore, qDot signals were associated with major recipient innate immune cells and promoted a shift in macrophages toward a regulatory phenotype in the lungs. ConclusionsOverall, this study demonstrates that HUCPVCs can successfully reduce systemic and neurological inflammation induced by LPS within the first 24 h after administration. Biodistribution and fate analyses suggest a critical role for the innate immune system in the HUCPVC-based immunomodulation mechanism.

Microglia-specific transcriptional repression of interferon-regulated genes after prolonged stress in mice

Stress-induced neuroinflammation is considered an important mechanism in the pathogenesis of depression. As immune effector cells in the brain, microglia play an essential role in neuroinflammation under stress, but the underlying mechanism remains controversial. Here, we performed RNA-seq and ATAC-seq to study microglia-specific epigenomic changes in mice after 12 weeks of exposure to mild stress. Our study revealed that chronic stress induced pronounced anxiety and depressive-like behavioral changes. However, microglia did not manifest a state of neuroinflammatory activation; instead, they displayed morphological changes characterized by hyper-ramification. Furthermore, we revealed large-scale transcriptional repression in microglia isolated from the stressed brain, including many interferon (IFN)-regulated genes (IRGs) and some encompassing DNA repeats. GSEA showed that the down-regulated genes were enriched in the IFN-mediated neuroimmune signaling pathways. In addition, integrative analysis with a published scRNA-seq dataset revealed that these down-regulated genes were enriched in a distinct subpopulation of “Interferon microglia”. ATAC-seq analysis further showed that differential gene expression was positively correlated with the changes in chromatin accessibility, and the IFN-stimulated response element (ISRE) was enriched in the down-regulated ATAC-seq loci. Interestingly, this phenotype was not associated with the production of IFNs. Instead, the gene encoding Activating Transcription Factor 3 (ATF3) was significantly increased in the stressed microglia, which might contribute to the transcriptional repression of IRGs. Our study reported microglia-specific transcriptional repression of IRGs independent of the production of IFNs, providing some new insights into neuroimmune dysregulation under prolonged stress.

Zinc Deficiency Blunts the Effectiveness of Antidepressants in the Olfactory Bulbectomy Model of Depression in Rats.

Currently used antidepressants do not always provide the desired results, and many patients suffer from treatment-resistant depression. Clinical studies suggest that zinc deficiency (ZnD) may be an important risk factor for depression and might blunt the effect of antidepressants. This study aimed to examine whether ZnD might blunt the effectiveness of antidepressants in the olfactory bulbectomy model (OB) of depression in rats. For this purpose, rats were subjected to the OB model, fed a zinc-deficient diet (3 mg Zn/kg) for 3 weeks, and finally treated with escitalopram (Esc), venlafaxine (Ven) 10 mg/kg, i.p., or combined Esc/Ven (1 mg/kg, i.p.) with zinc (5 mg/kg) for another 3 weeks. Open field (OFT), forced swim (FST), and sucrose intake (SIT) tests were used to evaluate depressive-like behavioral changes. In addition, serum, intracellular, and synaptic Zn concentrations and the level of zinc transporter (ZnT) proteins were analyzed. The OB + ZnD model induced hyperactivity in rats in the OFT, increased immobility time in the FST, and anhedonia in the SIT. Chronic treatment with Esc reduced immobility time in the FST in the OB + ZnD model. Esc/Ven +Zn increased sucrose intake in rats from the OB + ZnD group. The OB + ZnD decreased serum zinc levels and intracellular and synaptic Zn concentration in the prefrontal cortex (PFC) and cerebellum. These changes were normalized by chronic administration of Esc/Ven +Zn. Moreover, OB + ZnD decreased levels of the ZnT1 protein in the PFC and Hp and ZnT3 in Hp. Chronic administration of antidepressants did not alter the levels of ZnT proteins. The OB + ZnD model induces more depressive-like effects than either model alone. Our results show that ZnD may induce drug resistance in rats. Normalizing serum or brain zinc concentration is insufficient to reverse behavioral abnormalities caused by the OB + ZnD model. However, zinc supplementation might improve the effectiveness of antidepressants in reversing particular depression symptoms.

Xiaoyaosan Exerts Antidepressant-Like Effect by Regulating Autophagy Involves the Expression of GLUT4 in the Mice Hypothalamic Neurons

Many studies have proven that autophagy plays a pivotal role in the development of depression and it also affects the expression of GLUT4 in the hypothalamus. Xiaoyaosan has been shown to exert antidepressant effects in a variety of ways, but its underlying mechanism by which Xiaoyaosan regulates autophagy as well as GLUT4 in the hypothalamus remains unclear. Thus, in this study, we established a mouse model of depression induced by chronic unpredictable mild stress (CUMS), and set up autophagy blockade as a control to explore whether Xiaoyaosan exerts antidepressant effect by affecting autophagy. We examined the effects of Xiaoyaosan on behaviors exhibited during the open field test, tail suspension test and sucrose preference test, and the changes in autophagy in hypothalamic neurons as well as changes in GLUT4 and the related indicators of glucose metabolism in CUMS-induced depressive mouse model. We found that CUMS- and 3-MA-induced mice exhibited depressive-like behavioral changes, with decreased LC3 expression and increased p62 expression, suggesting decreased levels of autophagy in the mouse hypothalamus. The expression of GLUT4 was also decreased, and it was closely related to the level of autophagy through Rab8 and Rab10. Nevertheless, after the intervention of Xiaoyaosan, the above changes were effectively reversed. These results show that Xiaoyaosan can regulate the autophagy in hypothalamic neurons and the expression of GLUT4 in depressed mice.

Changes in depressive-like behaviors induced by spinal cord injury based on the hypothalamic-pituitary-adrenal axis and hippocampal neurogenesis.

A reduction in sucrose preference is a key characteristic of depressive-like behaviors after spinal cord injury as judged by the sucrose preference test, the hypothalamic-pituitary-adrenal axis and adult hippocampal neurogenesis. Male rats were divided into three groups: control, sham and spinal cord injury groups. The spinal cord injury rats received a severe mid-thoracic contusion. The Basso, Beattie and Bresnahan score was used to assess motor function. The sucrose preference test and forced swim test were used to evaluate depressive-like behaviors. Serum corticosterone levels were examined by enzyme-linked immunosorbent assay and hippocampal glucocorticoid receptor levels were examined by Western blot to evaluate the function of the hypothalamic-pituitary-adrenal axis. Adult hippocampal neurogenesis was assessed by testing hippocampal brain-derived neurotrophic factor and tropomyosin receptor kinase B levels by Western blot and doublecortin levels by immunohistochemistry. Data showed that spinal cord injury impaired motor function. The spinal cord injury rats exhibited decreased sucrose preference on day six, which continued to decrease until day twelve, followed by a plateau phase. Additionally, the immobility time of the spinal cord injury rats was increased on day thirty-four. Moreover, serum corticosterone levels in the spinal cord injury group peaked on day seven, was decreased by day twenty-one and was increased again on day thirty-five. Serum corticosterone levels were significantly negatively correlated with sucrose preference and positively correlated with immobility time. Finally, hippocampal doublecortin levels on days twenty-one and thirty-five were lower in the spinal cord injury group than in the other groups. These results suggest that hyperactivation of the hypothalamic-pituitary-adrenal axis and the inhibition of adult hippocampal neurogenesis may be part of the underlying mechanism responsible for depressive-like behaviors after spinal cord injury.

Antidepressant-like effects of cajaninstilbene acid and its related mechanisms in mice

Cajaninstilbene acid (CSA), a bioactive constituent isolated from pigeon pea leaves, exhibited neuroprotective activities in previous studies. The present study aims to evaluate the antidepressant effects of CSA by using behavioral despair models of tail suspension test (TST) and forced swimming test (FST), and a chronic unpredictable mild stress (CUMS) model. CSA (30 or 60 mg/kg), intragastrically administrated for 7 days, could significantly reduce the immobility time of mice in TST and FST. CSA treatment (15 or 30 mg/kg) significantly reversed the depressive-like behavioral changes of mice induced by 3 or 6 weeks CUMS that caused the decrease of sucrose preference, the increase of latency to feed in the novelty-suppressed feeding test, and the increase of immobility time in TST of mice. Furthermore, the related mechanisms of the effect were explored by accessing the metabolite levels of kynurenine pathway of tryptophan metabolism and the expression of some related proteins in cerebral cortex of CUMS mice. Our results showed that the kynurenine pathway was upregulated after CUMS, while the alteration could be significantly reversed by CSA. CSA also reversed the CUMS-induced decrease in the levels of BDNF, PSD-95, p-Akt/Akt and p-mTOR/mTOR. Therefore, the antidepressant-like effects of CSA might be achieved through regulating tryptophan metabolism, promoting BDNF and PSD-95 expression, and activating Akt/mTOR pathway in the cerebral cortex.

Analysis of genes linked to depressive‑like behaviors in interleukin‑18‑deficient mice: Gene expression profiles in the brain

Interleukin (IL)-18 is an interferon γ-inducing inflammatory cytokine associated with function of the immune system and other physiological functions. IL-18-deficient (Il18 -/-) mice exhibit obesity, dyslipidemia, non-alcoholic steatohepatitis and depressive-like behavioral changes. Therefore, IL-18 has a number of important roles associated with immunity, energy homeostasis and psychiatric conditions. In the present study, gene expression in the brains of Il18 -/- mice was analyzed to identify genes associated with the depressive-like behaviors and other impairments displayed by Il18 -/- mice. Using whole genome microarray analysis, gene expression patterns in the brains of Il18 +/+ and Il18 -/- mice at 6 and 12 weeks of age were examined and compared. Subsequently, genes were categorized using Ingenuity® Pathway Analysis (IPA). At 12 weeks of age, 2,805 genes were identified using microarray analysis. Genes related to 'Major depression' and 'Depressive disorders' were identified by IPA core analysis, and 13 genes associated with depression were isolated. Among these genes, fibroblast growth factor receptor 1 (Fgfr1); protein tyrosine phosphatase, non-receptor type 1 (Ptpn1); and urocortin 3 (Ucn3) were classed as depression-inducing and the other genes were considered depression-suppressing genes. Subsequently, the interactions between the microarray results at 6 weeks of age and the above three depression-inducing genes were analyzed to search for effector genes of depression at 12 weeks of age. This analysis identified cyclin D1 (Ccnd1) and NADPH oxidase 4 (Nox4). The microarray analysis results were correlated with the results of reverse transcription-quantitative PCR (RT-qPCR). Overall, the results suggest that Fgfr1, Ptpn1 and Ucn3 may be involved in depression-like changes and Ccnd1 and Nox4 regulate these three genes in IL-18-deficient mice.

Impairments in cognitive functions and emotional and social behaviors in a rat lithium-pilocarpine model of temporal lobe epilepsy

The aim of this study was to evaluate in detail behavioral patterns and comorbid disturbances in rats using the lithium-pilocarpine model. A comprehensive set of behavioral tests was used to investigate behavioral patterns, including the open field test, Morris water maze, Y-maze, fear conditioning, the elevated plus maze, the forced swimming test, and the resident-intruder paradigm. Motor and explorative activity, learning and memory, anxiety and depressive-like behavior, aggression, and communication were evaluated 8–15 d after pilocarpine-induced status epilepticus (SE) (latent phase of the model) and 41–53 d (chronic phase) after pilocarpine-induced SE. Increased motor activity and impaired memory function were the most noticeable behavioral modifications in the epileptic rats. Both the movement speed and distance traveled increased in the open field test in both the latent and chronic phases. Significant impairments were detected in short-and long-term spatial memory in the Morris water maze during the latent phase. Besides the alterations in spatial memory, behaviors indicative of short- and long-term fear-associated memory disturbances were observed in the fear conditioning test during the chronic phase of the model. In the resident-intruder paradigm, epileptic rats exhibited disturbed communicative behavior, with impaired social behaviors. In contrast, emotional disturbances were less prominent, with the rats exhibiting decreased anxiety. There were no changes in depressive-like behavior. The data suggest that the lithium-pilocarpine model of TLE in rodents is more useful for studies of comorbid disturbances in memory, hyperactivity, and social behavior than for research on psychoemotional impairments, such as anxiety and depression.

Lycopene Treatment Transposed Antidepressant-Like Action in Rats Provoked to Chronic Mild Stress

The present study aimed at evaluating the effects of lycopene on CMS-induced depressive-like behavioral changes in Wistar rats. In present study, rodents were selected randomly and grouped in to seven groups. Each group consists of six animals. All the groups are subjected to chronic mild stress in an unpredictable manner except the control group, which is free from stress. Behavioral changes induced during chronic mild stress were assessed by conducting the behavioral tests like forced swim test, sucrose preferences test, elevated plus maze test and open field tests in screening depressant and anxiety activity. The data analysis showed chronic mild stress produced depressive and anxiogenic behavior in the experimental rats. A significant increase in the immobility time and decrease in sucrose consumption in sucrose preference test are noted in CMS and vehicle groups. Similarly, in an elevated plus maze a significant decrease in the entries in the open arm and decrease in central square entries, and rearing behavior and increase in the duration of immobility were observed in open field test.Lycopene treatment for 6-weeks significantly decreased immobility time and increased in sucrose consumption observed in the forced swim test and sucrose preference test respectively. Lycopene significantly increased number of entries in the open arm of elevated plus maze and decreased grooming and freezing behavior in open field method. lycopene supplemented dose of 5mg/kg showed an insignificant results in all the behavioral models (p>0.05).The data were expressed as Mean±SD.Data were analyzed and differences between the means were determined by one-way analysis of variance (ANOVA) Using graph pad prism version 5.03 statistical software. In all the tests, differences were considered significant if p<0.05 to be a statistical significant. lycopene possesses antidepressant and mild- anxiolytic activity which may be due to its antioxidant effect that might warrant further studies.

Underlying mechanisms of recombinant adeno-associated virus-mediated bicaudal C homolog 1 overexpression in the medial prefrontal cortex of mice with induced depressive-like behaviors

Bicaudal C homolog 1 gene (BICC1) in the medial prefrontal cortex (mPFC) has been implicated in major depressive disorder (MDD); however, less is known about the mechanisms of BICC1-induced depression. The purpose of the present study was to investigate changes in depressive-like behaviors induced by recombinant adeno-associated virus (rAAV)-mediated overexpression of BICC1 in the mPFC of mice. A viral-mediated genetic approach was employed to explore the BICC1 overexpression-induced depressive-like behavioral and molecular changes in mice. For the first time, we found that BICC1 overexpression significantly induced depressive-like behaviors in mice. Further, the expression of disheveled-2 and the phosphorylation of Ser9 of glycogen synthase kinase 3β (GSK3β), mechanistic target of rapamycin (mTOR) and GluA1, GluA1, brain-derived neurotrophic factor (BDNF), and VGF were markedly down-regulated in BICC1 overexpression-treated animals. Our results demonstrate that the overexpression of BICC1 in the mPFC may induce depressive-like behaviors via GSK3β/mTOR signaling and GluA1 trafficking in the mPFC of mice, indicating that BICC1 may be a potential target for antidepressant treatment.

Chaihu-Shugan-San and absorbed meranzin hydrate induce anti-atherosclerosis and behavioral improvements in high-fat diet ApoE-/- mice via anti-inflammatory and BDNF-TrkB pathway

The comorbidity of coronary heart disease (CHD) and depression in patients is extremely prevalent, with a rate from 20 to 50%, while depression-like behaviors exist in a larger percentage of patients. Therefore, the study of comorbidities is particularly urgent. Chaihu-Shugan-San (CSS), a classical traditional Chinese medicine formula, has been used to treat CHD with depression for hundreds of years. However, the mechanism of its action on comorbidities remains unclear. Here, we focused on the behavioral changes in ApoE−/− mice fed a high-fat diet (HFD) and elucidated the mechanism of CSS and its main absorbed component, meranzin hydrate (MH), as an anti-atherosclerosis and anti-depression agent. In the present study, mice were fed an HFD for 16 weeks and were intragastrically administered high and low doses of CSS and MH. Depressive-like behaviors were evaluated by the sucrose preference test, the open-field test, the light-dark test and the tail-suspension test, after which atherosclerotic plaques, plasma lipids, inflammatory cytokine levels and the expression of BDNF/TrkB were measured. We demonstrated that the atherosclerosis model group exhibited significant depressant behaviors. Moreover, CSS inhibited depressive-like behavioral changes, reduced atherosclerotic plaque areas, plasma total cholesterol, triglycerides, LDL-cholesterol levels and inflammatory cytokines including TNF-α, IL-1β, and IL-6 in plasma and hippocampi, increased the protein and mRNA expression of BDNF and TrkB in the aorta and the hippocampus. Interestingly, MH, the main component in CSS that is absorbed in the plasma and hippocampus, exerted effects similar to those of CSS. In addition, MH increased the protein and mRNA expression of BDNF and TrkB in human umbilical vein endothelial cells (HUVECs) induced by LPS. Collectively, these results suggest that MH represents the CSS decoction, induces anti-atherosclerosis effects and improves depression-like behaviors in HFD-fed ApoE−/− mice. Moreover, the regulation of proinflammatory factors and BDNF-TrkB signaling are possibly involved in this process. Our findings indicate that MH is a potential phytochemical compound for the prevention of the comorbidity of atherosclerosis and depression.

Alteration of oxidative stress markers and behavior of rats in a novel model of depression

Emotional stress is considered a serious pathogenetic factor of depression. In this study an ultrasound model of emotional stress developed in our laboratory was applied. It is characterized by the use of ultrasound as the stressor agent. Animals are triggered not by any organic or physical disturbances but by the perception of adverse information. This type of stress can induce depressive-like behavioral changes in rodents, manifested by decreased sucrose preference and increased time of immobility in a forced swim test. Ultrasound stress also increased the levels of oxidative stress markers. This is important, as stress has an established association with increased oxidative processes in the central nervous system. Total glutathione and carbonyl protein content were selected as relevant brain markers, as glutathione plays a critical role in cellular defensive mechanisms during oxidative stress and the level of protein carbonyls can be a measure of global protein oxidation. We demonstrated that two weeks of chronic exposure to ultrasound was enough to cause depressive-like behavioral changes in rats. Increased levels of oxidative stress markers in the hippocampus and prefrontal cortex were also observed after two weeks of such stress. The current study has two goals: the first is to study the relationship of depression and oxidative stress; the second is an additional validation of our approach to modeling stress‑induced depressive-like states in rats. The present data further support the validity of the ultrasound model by expanding information related to the influence of ultrasound stress on behavioral and physiological parameters, which are of great importance in the development of stress-induced depression. A time correlation between the onset of symptoms and a change in the level of oxidative stress markers in the brain is also demonstrated.

SN003, a CRF1 receptor antagonist, attenuates depressive-like behavior and detrusor overactivity symptoms induced by 13-cis-retinoic acid in rats

Overactive bladder (OAB) often co-exists with depression in women. The corticotropin-releasing factor (CRF) system participates in the pathophysiology of both disorders. Therefore, we tested the effects of acute treatment with a reversible CRF receptor type-1 (CRF1) antagonist, SN003 (1mg/kg, i.v.), representatives of first (solifenacin, 0.03mg/kg, i.v.) and second (mirabegron, 1mg/kg, i.v.) line treatments for OAB as well as an antidepressant imipramine (30mg/kg, i.p.) on changes in depressive-like behavior and detrusor overactivity (DO) symptoms induced by a 6-week administration of 13-cis-retinoic acid (13-cis-RA, 1mg/kg/day, i.p.) in female Wistar rats, using in vivo cystometric investigations, forced swim test (FST) and spontaneous locomotor activity test. Following cystometric and behavioral studies, tissue was harvested and CRF level was assessed in the hypothalamus, amygdala and plasma. 13-cis-RA-induced depressive-like behavior and DO symptoms were associated with increased CRF levels in the hypothalamus, amygdala and plasma. Solifenacin and mirabegron attenuated DO symptoms induced by 13-cis-RA, did not display antidepressant-like activity and did not influence CRF levels in brain tissues or plasma. Imipramine and SN003 displayed antidepressant-like activity and lowered increased levels of CRF in brain tissues and plasma. Imipramine attenuated changes in some of the cystometric parameters, which are associated with OAB dry (without urge incontinence), whereas SN003 attenuated changes in almost all cystometric parameters that were induced by 13-cis-RA. CRF1 antagonist may be beneficial in case of OAB wet (with urge incontinence) or dry co-existing with depression. The possible mechanism may be related to the effects on central/peripheral CRF system.