Decreased Sucrose Consumption Research Articles

Kefir recovered depressive-like behaviour in CantonS lineage of Drosophila melanogaster exposed to chronic unpredictable mild stress protocol.

Chronic unpredictable mild stress (CUMS) is a widely accepted method for inducing depressive-like states in animal models. We decided to explore the effects of CUMS on the CantonS lineage of Drosophila melanogaster, which differs from the OregonR lineage in various ways. Additionally, we wanted to investigate the potential benefits of kefir in treating these chronically stressed flies, as previous research has shown promising results in using kefir components for depression treatment. To begin, we exposed male CantonS flies to a 10-day CUMS protocol and compared them to non-stressed flies. Within the stressed group, we had two subgroups: one treated with kefir (CUMS+ Kefir group) and the other treated with sertraline (positive control). We then analysed various factors including serotonin levels, brain structure, markers of oxidative damage in lipids and proteins, and behavioural manifestations such as sociability, locomotor function, and anhedonic-like behaviour. Our results showed that flies exposed to CUMS experienced a decrease in serotonin levels without any signs of degeneration. They also exhibited reduced sociability, increased motor agitation, and decreased sucrose consumption, which are all indicative of stress-induced depressive-like behaviour. However, treatment with sertraline partially reversed these effects. Interestingly, treatment with kefir not only restored serotonin levels but also improved sociability and anhedonic-like behaviours. Additionally, flies in the CUMS+ Kefir group had a longer lifespan compared to their untreated counterparts. These findings suggest that kefir has multiple advantageous effects on flies subjected to the 10-day CUMS protocol. In conclusion, our study demonstrates that the CantonS lineage of D. melanogaster displays depressive-like manifestations after exposure to CUMS. Furthermore, kefir emerges as a powerful nutritional tool capable of reversing these effects and promoting beneficial outcomes in chronically stressed flies.

Transcriptome analysis of rats with chronic unpredictable mild stress treated with electroacupuncture.

Depression remains one of the most prevalent psychiatric disorders, with many patients not responding adequately to available treatments. Electroacupuncture (EA), a nonpharmacologic therapy, holds great promise for alleviating depressive symptoms. In this study, RNA sequencing (RNA-Seq) was used to identify genome-wide alterations in the hippocampus of rats after chronic unpredictable mild stress (CUMS) and EA treatments to further elucidate the mechanism by which EA ameliorates depression to provide a basis for the clinical application of EA in stress-related diseases. The sucrose preference test (SPT), open field test (OFT), and forced swimming test (FST) were used to investigate the ability of EA at Baihui (GV20) and Taichong acupoints (LR3) to improve depression-like behavior in rats subjected to CUMS. Subsequently, RNA-Seq analysis revealed transcriptomic profiles of the hippocampus of rats subjected to CUMS in which EA ameliorated depressive behavior. Finally, the expression profiles of major differentially expressed genes were tested by real-time quantitative polymerase chain reaction (qRT-PCR) to determine the accuracy of the RNA-Seq results. Rats subjected to CUMS exhibited depressive-like behaviors, such as decreased sucrose consumption in the SPT (p<.001), decreased time in the central area of the OFT (p<.001), and increased immobility in the FST (p<.01). Importantly, rats subjected to CUMS and treated with EA showed increased sucrose consumption (p<.001), increased time spent in the central area of the OFT (p<.001) and decreased immobility in the FST (p<.01). Sixty-three genes that were differentially expressed following CUMS were altered by EA; most of these were associated with immune pathways. Compared with those in the control group, the expression levels of Colla2 (p<.001), Col3a1 (p<.001), Psmb9 (p<.01), and Tap1 (p<.01) in the hippocampus of rats subjected to CUMS were lower. The changes in the expression of these genes were reversed by EA treatment. EA at GV20 and LR3 attenuated CUMS-induced depression-like behaviors by regulating the expression of specific genes such as Colla2, Col3a1, Psmb9, and Tap1.

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

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

Mechanistic insights into the anti-depressant effect of curcumin based on network pharmacology and experimental validation.

Curcumin (CUR) exhibits a definite curative effect in the treatment of depression. To identify potential antidepressant targets and mechanisms of action of CUR. This study used network pharmacology to explore the signaling pathways and CUR-related targets in depression. C57BL/6J mice (male,12-14weeks old) were randomly divided into four groups (n = 8): saline-treated (control mice), lipopolysaccharide (LPS, 2mg/kg/day, intraperitoneally), LPS + CUR (50mg/kg/day, intragastrically), and LPS + CUR + LY294002 (7.5mg/kg/day, intraperitoneally). After 1week, behavioral tests were performed. Then, neuronal damage in the prefrontal cortex of mice was evaluated by hematoxylin-eosin (HE) staining. We uncovered the main active mechanism of CUR against depression using Western blotting and enzyme-linked immunosorbent assay (ELISA). Gene set enrichment analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that the most significantly enriched pathway in CUR against depression was the PI3K-Akt pathway. Moreover, 52 targets were significantly correlated with the PI3K-Akt signaling pathway and CUR-related targets. In addition, among the top 50 targets ranked by degree in the protein-protein interaction (PPI) network, there were 23 targets involved in the 52 intersection targets. Administration of LPS alone extended immobility time in the open field test (OFT) and tail suspension test (TST) and decreased sucrose consumption in the sucrose preference test (SPT). Pretreatment with CUR relieved LPS-induced changes in the behavioral tests, activity of the PI3K-Akt signaling pathway, neuronal damage in the prefrontal cortex (PFC), and inflammatory response. Moreover, inhibition of the PI3K-Akt signaling pathway by LY294002 blocked the therapeutic effects of CUR. Our study indicates that CUR may be an effective antidepressant agent in an LPS-induced mouse model, partly because of its anti-inflammatory action through the PI3K-Akt signaling pathway.

Prelimbic Cortical Stimulation Induces Antidepressant-like Responses through Dopaminergic-Dependent and -Independent Mechanisms.

High-frequency stimulation (HFS) is a promising therapy for patients with depression. However, the mechanisms underlying the HFS-induced antidepressant-like effects on susceptibility and resilience to depressive-like behaviors remain obscure. Given that dopaminergic neurotransmission has been found to be disrupted in depression, we investigated the dopamine(DA)-dependent mechanism of the antidepressant-like effects of HFS of the prelimbic cortex (HFS PrL). We performed HFS PrL in a rat model of mild chronic unpredictable stress (CUS) together with 6-hydroxydopamine lesioning in the dorsal raphe nucleus (DRN) and ventral tegmental area (VTA). Animals were assessed for anxiety, anhedonia, and behavioral despair. We also examined levels of corticosterone, hippocampal neurotransmitters, neuroplasticity-related proteins, and morphological changes in dopaminergic neurons. We found 54.3% of CUS animals exhibited decreased sucrose consumption and were designated as CUS-susceptible, while the others were designated CUS-resilient. HFS PrL in both the CUS-susceptible and CUS-resilient animals significantly increased hedonia, reduced anxiety, decreased forced swim immobility, enhanced hippocampal DA and serotonin levels, and reduced corticosterone levels when compared with the respective sham groups. The hedonic-like effects were abolished in both DRN- and VTA-lesioned groups, suggesting the effects of HFS PrL are DA-dependent. Interestingly, VTA-lesioned sham animals had increased anxiety and forced swim immobility, which was reversed by HFS PrL. The VTA-lesioned HFS PrL animals also had elevated DA levels, and reduced p-p38 MAPK and NF-κB levels when compared to VTA-lesioned sham animals. These findings suggest that HFS PrL in stressed animals leads to profound antidepressant-like responses possibly through both DA-dependent and -independent mechanisms.

Depressive-like Behavior Is Accompanied by Prefrontal Cortical Innate Immune Fatigue and Dendritic Spine Losses after HIV-1 Tat and Morphine Exposure.

Opioid use disorder (OUD) and HIV are comorbid epidemics that can increase depression. HIV and the viral protein Tat can directly induce neuronal injury within reward and emotionality brain circuitry, including the prefrontal cortex (PFC). Such damage involves both excitotoxic mechanisms and more indirect pathways through neuroinflammation, both of which can be worsened by opioid co-exposure. To assess whether excitotoxicity and/or neuroinflammation might drive depressive behaviors in persons infected with HIV (PWH) and those who use opioids, male mice were exposed to HIV-1 Tat for eight weeks, given escalating doses of morphine during the last two weeks, and assessed for depressive-like behavior. Tat expression decreased sucrose consumption and adaptability, whereas morphine administration increased chow consumption and exacerbated Tat-induced decreases in nesting and burrowing-activities associated with well-being. Across all treatment groups, depressive-like behavior correlated with increased proinflammatory cytokines in the PFC. Nevertheless, supporting the theory that innate immune responses adapt to chronic Tat exposure, most proinflammatory cytokines were unaffected by Tat or morphine. Further, Tat increased PFC levels of the anti-inflammatory cytokine IL-10, which were exacerbated by morphine administration. Tat, but not morphine, decreased dendritic spine density on layer V pyramidal neurons in the anterior cingulate. Together, our findings suggest that HIV-1 Tat and morphine differentially induce depressive-like behaviors associated with increased neuroinflammation, synaptic losses, and immune fatigue within the PFC.

The combination of chronic stress and smoke exacerbated depression-like changes and lung cancer factor expression in A/J mice: Involve inflammation and BDNF dysfunction.

Depression is positively correlated with the high incidence and low survival rate of cancers, while more cancer patients suffer depression. However, the interaction between depression and cancer, and possible underline mechanisms are unclear. Chronic unpredictable mild stress (CUMS) was used to induce depression, and smoke to induce lung cancer in lung cancer vulnerable AJ mice. After 8 weeks, sucrose preference and forced swimming behaviors were tested. Blood corticosterone concentration, and levels of cytokines, lung cancer-related factors, brain-derived neurotrophic factor (BDNF) and apoptosis-related factors in the lung, amygdala and hippocampus were measured. Compared to control group, CUMS or smoke decreased sucrose consumption and increased immobility time, which were deteriorated by stress+smoke. CUMS, smoke or both combination decreased mononuclear viability and lung TNF-α concentration, increased serum corticosterone and lung interleukin (IL)-1, IL-2, IL-6, IL-8, IL-10, IL-12 and HSP-90α concentrations. Furthermore, stress+smoke caused more increase in corticosterone and IL-10, but decreased TNF-α. In parallel, in the lung, Bcl-2/Bax and lung cancer-related factors CDK1, CDC20, P38α etc were significantly increased in stress+smoke group. Moreover, CUMS decreased BDNF, while CUMS or smoke increased TrkB and P75 concentrations, which were exacerbated by stress+smoke. In the amygdala, except for CUMS largely increased Bax/Bcl-2 and decreased TrkB, each single factor decreased BDNF and IL-10, but increased P75, IL-1β, IL-12, TNF-α concentrations. Changes in Bax/Bcl-2, IL-10 and TNF-α were further aggravated by the combination. In the hippocampus, except for CUMS largely increased P75 concentration, each single factor significantly increased Bax/Bcl-2 ratio, IL-1β and TNF-α, but decreased BDNF, TrkB and IL-10 concentrations. Changes in Bax, Bax/Bcl-2, IL-10 and TNF-α were further aggravated by the combination. These results suggest that a synergy between CUMS and smoke exposure could promote the development of depression and lung cancer, through CUMS increased the risk of cancer occurrence, and conversely lung cancer inducer smoke exposure deteriorated depressive symptoms.

Effect of a brain-penetrant selective estrogen receptor degrader (SERD) on binge drinking in female mice.

BackgroundGreater circulating levels of the steroid hormone 17β‐estradiol (E2) are associated with higher levels of binge drinking in women. In female mice, estrogen receptors in the ventral tegmental area, a dopaminergic region of the brain involved in the motivation to consume ethanol, regulate binge‐like ethanol intake. We recently developed a brain‐penetrant selective estrogen receptor degrader (SERD), YL3‐122, that could be used to test the behavioral role of brain estrogen receptors. We hypothesized that treating female mice with this compound would reduce binge‐like ethanol drinking.MethodsFemale C57BL/6J mice were treated systemically with YL3‐122 and a related SERD with low brain penetrance, XR5‐27, and tested for binge‐like ethanol consumption in the drinking in the dark (DID) test. Mice were also tested for sucrose and water consumption and blood ethanol clearance after treatment with the SERDs. Finally, the effect of ethanol exposure on Esr1 gene expression was measured in the ventral tegmental area (VTA), prefrontal cortex (PFC), and ventral hippocampus (vHPC) of male and female mice by quantitative real‐time PCR after 4 DID sessions.ResultsYL3‐122 reduced ethanol consumption when mice were in diestrus but not estrus. YL3‐122 also decreased sucrose consumption but did not alter water intake or blood ethanol clearance. XR5‐27 did not affect any of these measures. Binge‐like ethanol drinking resulted in increased Esr1 transcript in the VTA of both sexes, male vHPC, and female PFC.ConclusionsThese results indicate that SERD treatment can decrease binge‐like ethanol drinking in female mice. Thus, it could be a novel strategy to reduce binge drinking in women, with the caveat that effectiveness may depend on menstrual cycle phase. In addition, Esr1 transcript is increased by binge ethanol exposure in both sexes but in a brain region‐specific manner.

Interleukin-10 Attenuates Behavioral, Immune and Neurotrophin Changes Induced by Chronic Central Administration of Interleukin-1β in Rats

Background: Activated microglia can trigger pro-inflammatory cytokine releases and neuroinflammation, which may inhibit astrocytes to produce neurotrophins and anti-inflammatory factors. Both eventually lead to neuron apoptosis or death. Furthermore, effective antidepressant or anti-dementia treatments can reduce pro-inflammatory cytokines, while enhance interleukin (IL)-10 production. However, the underline mechanism by which IL-10 modulates glial cell function, hence improves cognitive impairment or depression-like behavior is unknown. This study evaluated whether and how IL-10 attenuated chronic IL-1β administration-induced behavioral changes and the possible involved mechanisms. Methods: Rats received intracerebroventricular injection of IL-1β and/or IL-10 for 14 days. Then animal memory and depression-like behavior, pro-inflammatory cytokines, glial activities, expression of brain-derived neurotrophic factor (BDNF), Trk B, p75, and apoptosis-related genes were studied. Results: Compared to controls, significantly increased latent time and swimming distance in the Morris-water-maze, decreased sucrose consumption, and decreased locomotor and center zone entries in the open-field were found in rats administrated with IL-1β. These changes were associated with the reduction of GFAP expression, and concentrations of BDNF and anti-inflammatory cytokine IL-10, but the increase in the expressions of CD11b, TrkB, p75, and Caspase-3, the ratio of Bax/Bcl-2, and the concentrations of IL-1β, tumor necrosis factor-α, and IL-6. IL-10 treatment markedly attenuated IL-1β-induced above changes, except for the expressions of neurotrophin receptors. Conclusion: IL-10-improved behavioral changes may be through suppressing microglia activity and inflammation, while restoring astrocyte function and BDNF expression.

Gender-based differences in neuroprotective effects of hydrogen gas against intracerebral hemorrhage-induced depression

BackgroundPost-stroke depression (PSD) severely affects recovery in patients with intracerebral hemorrhage (ICH). Although hydrogen gas (H2) exerts excellent neuroprotective effects in patients with ICH, there are sex-based differences in H2 efficacy in several diseases. Herein, we determined whether estrogen increases susceptibility to the neuroprotective effects of H2 in males with ICH-induced depression. MethodsA rodent model of ICH in the basal ganglia was established using autologous blood injection (30 μL). Mice were treated with 2.9% H2 for 2 h daily for 3 days post-ICH. Estrogen (1 mg/kg) was administered by subcutaneous injection daily for 3 days to male mice post-ICH. Thirty days post-ICH, PSD was evaluated by sucrose preference, forced swimming, and 3-chamber social tests. Following the completion of behavioral tests, levels of superoxide dismutase (SOD) and reactive oxygen species (ROS), astrocytic activation, phosphorylated (p)–NF–κB-positive astrocytes, p–NF–κB, p-IKKβ, IL-1β, and IL-6 expression were determined. ResultsCompared with female mice, H2 administration post-ICH exhibited fewer neuroprotective effects, including decreased sucrose consumption and time spent sniffing a novel mouse, increased immobility time, downregulated total SOD content, upregulated ROS content and p–NF–κB levels, and elevated astrocyte branches, whereas estrogen enhanced the neuroprotective effects of H2 in male mice. A reduced number of p–NF–κB-positive astrocytes, downregulated expression of p–NF–κB, p-IKKβ, IL-1β, and IL-6 in the amygdala were demonstrated in ICH-males treated with estrogen plus H2. ConclusionsEstrogen was responsible for increased H2 sensitivity in male mice with ICH. The underlying mechanism may be associated with the suppression of NF-κB signaling in astrocytes.

Brain-derived neurotrophic factor upregulates synaptic GluA1 in the amygdala to promote depression in response to psychological stress

Psychological stress impairs neuronal structure and function and leads to emotional disorders, but the underlying mechanisms have not yet been fully elucidated. The amygdala is closely correlated with emotional regulation. In the present study, we analyzed whether the amygdala plasticity is regulated by psychological stress and explored their regulatory mechanism. We established a mouse psychological stress model using an improved communication box, wherein mice were exposed to chronic fear and avoided physical stress interference. After the 14-day psychological stress paradigm, mice exhibited significantly increased depressive behaviors (decreased sucrose consumption in the sucrose preference test and longer immobility time in the forced swimming test). HPLC, ELISA, and molecular and morphological evidences showed that psychological stress increased the content of glutamate and the expression of glutamatergic neurons, upregulated the content of the stress hormone corticosterone, and activated the CREB/BDNF pathway in the amygdala. Furthermore, psychological stress induced an increased density of dendritic spines and LTD impairment in the amygdala. Importantly, virus-mediated silencing of BDNF in the basolateral amygdala (BLA) nuclei reversed the depression-like behaviors and the increase of synaptic GluA1 and its phosphorylation at Ser831 and Ser845 sites in psychologically stressed mice. This process was likely achieved through mTOR signaling activation. Finally, we treated primary amygdala neurons with corticosterone to mimic psychological stress; corticosterone-induced upregulation of GluA1 was prevented by BDNF and mTOR antagonists. Thus, activation of the CREB/BDNF pathway in the amygdala following psychological stress upregulates synaptic GluA1 via mTOR signaling, which dysregulates synaptic plasticity of the amygdala, eventually promoting depression.

Korean red ginseng alleviate depressive disorder by improving astrocyte gap junction function

Korean red ginseng (KRG), a processed product of Panax ginseng C. A. Mey, show significant anti-depressive effect in clinic. However, its mechanism is still unclear. Gap junction intercellular communication (GJIC) dysfunction is a potential pathogenesis of depression. Therefore, this study's objective is to investigate whether the antidepressant effect of KRG is related to GJIC. Rat were restraint 8h every day for 28 consecutive days to prepare depression models, and meanwhile, rats were intragastrically administrated with normal saline, KRG solutions (25, 50 or 100mg/kg) or fluoxetine (10mg/kg) 1h before stress. The behavioral performance was determined by forced swimming test, sucrose preference test and open field test. GJIC was determined by the Lucifer yellow (LY) diffusion distance in prelimb cortex (PLC). In addition, the level of Cx43, one of executors of GJIC, was tested by Western blot. To find out the protective effect of KRG against GJIC dysfunction directly, rats were intracranially injected with carbenoxolone (CBX, blocker of GJIC), and meanwhile normal saline, KRG (100mg/kg) or fluoxetine (10mg/kg) was administered daily. The behavioral performance of these rats was detected, and the LY localization injection PLC area was used to detect the gap junction function. Chronic resistant stress (CRS) induced depressive symptoms, as manifested by prolonged immobility time in forced swimming test and decreased sucrose consumption ratio. Administration of KRG alleviated these depressive symptoms significantly. GJIC determination showed that KRG improved the LY diffusion and increased Cx43 level in prefrontal cortex (PFC) significantly, indicated that GJIC dysfunction was alleviated by the treatment of KRG. However, the astrocytes number was also increased by the treatment of KRG, which maybe alleviate depression-like symptoms by increasing the number of astrocytes rather than improving GJIC. Injection of CBX produced depressive symptoms and GJIC dysfunction, as manifested by decreased sucrose consumption ratio and prolonged immobility time in forced swimming test, but no astrocytes number changes, KRG also reversed depressive symptoms and GJIC dysfunction, suggested that the improvement of depressive-like symptoms was improved by GJIC. KRG alleviate depressive disorder by improving astrocytic gap junction function.

Endogenous ω-3 fatty acids in Fat-1 mice attenuated depression-like behaviors, spatial memory impairment and relevant changes induced by olfactory bulbectomy

ObjectivesOlfactory bulbectomy (OB) induced behaviors, hypercortisolism, inflammation and neurotrophin dysfunctions are similar to those observed in depressed patients. Omega (n)-3 polyunsaturated fatty acids (PUFAs) can effectively treat depression via anti-inflammatory and neuroprotective effects. However, n-3 PUFA purities, caloric contents, and ratios in different diets often cause contradictive results. This study used Fat-1 mice, which can convert n-6 to n-3 PUFAs in the brain, to study the effect of n-3 PUFAs on OB-induced behaviors and related changes. MethodsFat-1 and wild-type littermates were fed safflower oil for 3 months. Behaviors were tested on day 21 after surgery. Monoamine neurotransmitters were measured by HPLC. Macrophage activity was measured by MTT assay. Astrocyte phenotypes A1 S100β, A2 BDNF and cholesterol level were measured by ELISA and total cholesterol assay kits respectively. PUFA profile and membrane fluidity were detected by GC and DPH fluorescence probe respectively. ResultsOB significantly induced animal hyperactivity and spatial memory impairment, while decreased sucrose consumption and social contact with decreased 5-HT turnover, increased the macrophage activity and S100β/BDNF ratio. Meanwhile, n-3/n-6 PUFAs ratio and total cholesterol level were reduced in OB mice. Whereas, OB-induced behavioral changes were attenuated, which were associated with increasing 5-HT turnover, decrease macrophage activity, restored S100β/BDNF and n-3/n-6 PUFAs ratios, and total cholesterol concentrations in Fat-1 mice. ConclusionThe present study for the first time demonstrated that endogenous n-3 PUFAs attenuated OB-induced depression-like behaviors and spatial memory impairment through modulating serotonergic and immune function, balancing the astrocyte A1/A2 phenotypes, and normalizing PUFAs profile and membrane function.

Young plasma administration mitigates depression-like behaviours in chronic mild stress-exposed aged rats by attenuating apoptosis in prefrontal cortex.

What is the central question of this study? Young plasma contains several rejuvenating factors that exert beneficial effects in ageing and neurodegenerative diseases: can repeated transfusion of young plasma improve depressive behaviour in aged rats? What is the main finding and its importance? Following chronic transfusion of young plasma, depressive behaviour was improved in the depression model of aged rats, which was associated with reduced apoptosis process in the prefrontal cortex. Brain ageing alters brain responses to stress, playing an essential role in the pathophysiology of late-life depression. Moreover, apoptotic activity is up-regulated in the prefrontal cortex in ageing and stress-related mood disorders. Considerable evidence suggests that factors in young blood could reverse age-related dysfunctions in organs, especially in the brain. Therefore, this study investigated the effect of young plasma administration on depressive behaviours in aged rats exposed to chronic unpredictable mild stress (CUMS), with a focus on the apoptosis process. Young (3months old) and aged (22months old) male rats were randomly assigned into four groups: young control (YC), aged control (AC), aged rats subjected to CUMS (A+CUMS) and aged rats subjected to CUMS and treated with young plasma (A+CUMS+YP). In the A+CUMS and A+CUMS+YP groups, CUMS was used to generate the depression rat model. Moreover, the A+CUMS+YP group received pooled plasma (1ml, intravenously), collected from young rats, three times per week for 4weeks. Young plasma administration significantly improved CUMS-induced depression-like behaviours, including decreased sucrose consumption ratio, reduced locomotor activity and prolonged immobility time. Importantly, young plasma reduced neuronal apoptosis in the prefrontal cortex that was associated with reduced TUNEL-positive cells and cleaved caspase-3 protein levels in the A+CUMS+YP compared with the A+CUMS group. Young plasma can partially improve the neuropathology of late-life depression through the apoptotic signalling pathways.

Tetragonia tetragonioides Relieves Depressive-Like Behavior through the Restoration of Glial Loss in the Prefrontal Cortex

Tetragonia tetragonioides, which is a halophyte and grows widely in Asian-Pacific regions, has been used for the treatment of digestive disorders in traditional oriental medicine. This study examined the potential antidepressant effect of Tetragonia tetragonioides in an astroglial degeneration model of depression, which was established based on the postmortem study of depressive patients' brain presenting diminished astrocytes in the prefrontal cortex. C57BL/6 male mice were exposed to glial ablation in the prefrontal cortex by the administration of the gliotoxin, L-alpha-aminoadipic acid (L-AAA) to induce depression. Tetragonia tetragonioides at doses of 100 mg/kg and 300 mg/kg, imipramine at a dose of 15 mg/kg, and distilled water were orally administrated to mice for 18 days. Behavioral tests including the open field test (OFT), sucrose preference test (SPT), forced swimming test (FST), and tail suspension test (TST) were carried out after 2 days of L-AAA injection. The expression levels of GFAP and NeuN in the prefrontal cortex were determined by immunohistochemistry. Mice subjected to glial ablation in the prefrontal cortex displayed decreased sucrose consumption in SPT and increased immobility time in FST and TST. Treatment with imipramine and Tetragonia tetragonioides remarkably ameliorated the behavioral despair induced by L-AAA. In addition, immunohistochemistry analysis showed that treatment with Tetragonia tetragonioides significantly restored the glial loss as indicated by the elevated GFAP expression level. These findings suggest that Tetragonia tetragonioides exerts an antidepressant effect through the restoration of glial loss under conditions of depression and can be a candidate for an antidepressant agent.

Early Life Stress Increases Brain Glutamate and Induces Neurobehavioral Manifestations in Rats.

Early life stress (ELS) is associated with an increased risk of developing depression and anxiety disorders. Disturbances of the neurobiological glutamatergic system are implicated in depression; however, the long-term effects of ELS on glutamate (Glu) metabolites remain unclear. Our study used 7T proton magnetic resonance spectroscopy (7T 1H MRS) to detect metabolic Glu in a rat model to investigate maternal deprivation (MD)-induced ELS. MD was established in Sprague-Dawley rats by periodic separation from mothers and peers. Changes in the hippocampal volume and Glu metabolism were detected by 7T 1H MRS after testing for depression-like behavior via open field, sucrose preference, and Morris water maze tests. Adult MD offspring exhibited depression-like behavior. Compared to the control, the MD group exhibited reduced ratio of central activity time to total time and decreased sucrose consumption (p < 0.05). MD rats spent less time in the fourth quadrant, where the platform was originally placed, in the Morris water maze test. According to 7T 1H MRS, hippocampus of MD rats had elevated Glu and glutamate + glutamine (Glu+Gln) levels compared with the control group hippocampi, but Gln, γ-aminobutyric acid (GABA), and glutamate + glutamine (Glu+Gln) in the prefrontal cortex of MD rats showed a downward trend. Depression-like behavior and cognition deficits related to ELS may induce region-specific changes in Glu metabolism in the prefrontal cortex and hippocampus. The novel, noninvasive 7T 1H MRS-identified associations between Glu levels and ELS may guide future clinical studies.

A Study of Antidepressant Effect and Mechanism on Intranasal Delivery of BDNF-HA2TAT/AAV to Rats with Post-Stroke Depression.

AimPost-stroke depression (PSD) is one of the most frequent neuropsychiatric disorders associated with stroke characterized by depression. The neuroplasticity hypothesis postulates that loss of brain-derived neurotrophic factor (BDNF) plays a major role in pathophysiology of PSD, and restoration of it may represent a critical mechanism underlying antidepressant efficacy.MethodsIn previous studies, we designed a new fusion gene, HA2TAT-BDNF, and cloned it into adenovirus associated virus (AAV) to construct the BDNF-HA2TAT/AAV for the delivery of BDNF to central nervous system (CNS) via nose-brain pathway. In this study, we used it to explore the antidepressant effects on PSD rats through behavioral and various histological methods, and try to find out its specific mechanism.ResultsCompared with the control group, the PSD+AAV group showed decreased sucrose consumption percentage in the sucrose preference test (SPT) (P < 0.001) and prolonged immobility in the forced swimming test (FST) (P=0.000). However, the nasal administration of BDNF-HA2TAT/AAV reversed results of these two behavioral tests (P>0.05, P >0.05), showing an adequate antidepressant effect. Compared with the control group, the concentrations of BDNF mRNA and protein in the hippocampus (P< 0.05, P < 0.01) and prefrontal cortex (P < 0.01, P < 0.01) of PSD rats both decreased. Increased BDNF mRNA and protein expression was observed in the prefrontal cortex (P > 0.05, P < 0.05), without notable change in the hippocampus (P < 0.05, P < 0.001) of PSD+BDNF rats.ConclusionThese results suggest that BDNF reductions in the prefrontal cortex and hippocampus are associated with the development of post-stroke depression, and that increased levels of BDNF in the prefrontal cortex could be used as a therapeutic target to treat PSD. However, the exact mechanism of BDNF action remains unclear in this regard, hindering the wider application of our method. We expect that our research could facilitate the exploration of pathogenesis and the new treatment method of PSD.

Oleuropein Reverses Repeated Corticosterone-Induced Depressive-Like Behavior in mice: Evidence of Modulating Effect on Biogenic Amines

Depression is still one of challenging, and widely encountered disorders with complex etiology. The role of healthy diet and olive oil in ameliorating depression has been claimed. This study was designed to explore the effects of oleuropein; the main constituent of olive oil; on depression-like behaviors that are induced by repeated administration of corticosterone (40 mg/kg, i.p.), once a day for 21 days, in mice. Oleuropein (8, 16, and 32 mg/kg, i.p.) or fluoxetine (20 mg/kg, positive control, i.p.1) was administered 30 minutes prior to corticosterone injection. Sucrose consumption test, open-field test (OFT), tail suspension test (TST), and forced swimming test (FST) were performed. Reduced Glutathione (GSH), lipid peroxidation, and biogenic amines; serotonin, dopamine, and nor-epinephrine; levels were also analyzed in brain homogenates. Corticosterone treatment induced depression-like behaviors, it increased immobility time in the TST, OFT, and FST, decreased the number of movements in OFT, and decreased sucrose consumption. Corticosterone effect was associated with depletion of reduced glutathione and increase of lipid peroxidation, in addition to modification of biogenic amines; decreased serotonin and dopamine. Oleuropein or fluoxetine administration counteracted corticosterone-induced changes. In conclusion, oleuropein showed a promising antidepressant activity, that is evident by improving corticosterone-induced depression-like behaviors, and normalizing levels of biogenic amines.

Early Life Stress Increases Brain Glutamate and Induces Neurobehavioral Manifestations in Rats

Background: Early life stress (ELS) is associated with an increased risk of developing depression and anxiety disorders. Disturbances of the neurobiological glutamatergic system are implicated in depression; however, the long-term effects of early life stress on glutamate (Glu) metabolites remain unclear. Our study used 7T proton magnetic resonance spectroscopy (7T 1 HMRS) to detect metabolic Glu in a rat model to investigate maternal deprivation (MD)-induced ELS. Methods: MD was established in Sprague-Dawley rats by periodic separation from mothers and peers. Changes in the hippocampal volume and Glu metabolism were detected by 7T 1 HMRS after testing for depression-like behavior via open field, sucrose preference, and Morris water maze tests. Findings: Adult MD offspring exhibited depression-like behavior. Compared to control, the MD group exhibited reduced ratio of central activity time to total time and decreased sucrose consumption (18 ± 6 g vs. 31 ± 12 g, p = 0·02). MD rats spent less time in the fourth quadrant, where the platform was originally placed, in the Morris water maze test. According to 7T 1 HMRS, MD rats had elevated Glu and glutamate+glutamine (Glu+Gln) levels compared with the control group hippocampi, but Gln and gamma-aminobutyric acid (GABA), glutamate+glutamine (Glu+Gln) in the prefrontal cortex of MD rats showed a downward trend. Interpretation: Depression-like behavior and cognition deficits related to ELS may induce region-specific changes in Glu metabolism in the prefrontal cortex and hippocampus. The novel, noninvasive 7T 1 HMRS-identified associations between Glu levels and ELS may guide future clinical studies. Funding Statement: The Key Program of the National Natural Science Foundation of China, No. 30930027; Program of the National Natural Science Foundation of China, No. 60971075; Natural Science Foundation of Guangdong Province of China, Nos.S2011010005194 and 2015A030313444; Shantou University Scientific Research Foundation for the Doctoral Scholar of China, No.NTF10010; The Department of Education, Guangdong Government under the Top-tier University Development Scheme for Research and Control of Infectious Diseases of China, No. 2015034. Declaration of Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethics Approval Statement: All procedures used in the study were reviewed and approved by the Ethics Committee of School of Medicine, Shantou University Medical College, and comply with the National Institutes of Health’s Guide for the Care and Use of Laboratory Animals (NIH publication no. 85-23, revised 1985). In the handling and care of all animals, we followed the international guiding principles for animal research, as stipulated by the World Health Organization (WHO) Chronicle (World Health Organization, 1985), as adopted by the Laboratory Animal Center, Shantou University Medical College.

Decreased serotonin content and release in the ventral hippocampus of prenatally stressed male rats in response to forced swim test

Prenatal stress modifies the serotonergic system by altering the synthesis, metabolism, receptors and serotonin content in the hippocampus. However, it is currently unknown whether serotonin release in the ventral hippocampus of prenatally stressed rats is altered. In this study, serotonin (5-HT) and its metabolite, 5‑hydroxyindoleacetic acid (5-HIAA) levels were analysed in dialysates (in vivo) and in homogenates (in vitro) of the ventral hippocampus. This was made after the sucrose preference test and after forced swim test (FST) in male adult progeny from mothers that were stressed by immersion in cold water during the last week of gestation. Serum concentration of corticosterone was also evaluated in control and in prenatally stressed males. Sucrose preference was differently affected in prenatally stressed males: 69% showed decreased sucrose consumption, and were considered anhedonic; 31% exhibited sucrose consumption similar to control and were considered non‑anhedonic. During the FST, increased immobility and decreased swimming were observed in prenatally stressed males. After sucrose test, content and release of 5‑HT in prenatally stressed rats were similar to those in the control group, with higher metabolite. After the FST, 5-HT content increased, but its release increased slightly in anhedonic rats and did not change in non-anhedonic rats, with lower metabolite. The response of the adrenal axis to the FST was larger in anhedonic prenatally stressed males, than in control and non‑anhedonic males. These data show that behavioural disruption caused by prenatal stress is related to low release and lower metabolism of serotonin in the ventral hippocampus in adult male offspring, as well as to hyperactivity and hyperreactivity of the adrenal axis.