Depressed Rat Research Articles

Antidepressive and cardioprotective effects of Kai-xin-san via the regulation of HPA axis dysfunction and lipid metabolism in a rat model of depressive-cardiac disease

Depressive-cardiac disease is a comorbid state in which both cardiovascular diseases and mental disorders are present. Patients with depression are more likely to develop cardiovascular disease, which increases the risk of cardiovascular events, such as acute coronary syndrome. Cardiovascular diseases also exacerbate the poor mood of patients with psychiatric disorders. Kai-xin-san (KXS), a classic antidepressant formula, has potential antidepressive and cardioprotective effects. In the present study, we first evaluated the antidepressive and cardioprotective effects of KXS in two post-myocardial ischemic depressed rat models: a) isoproterenol (ISO) via intraperitoneal injection combined with chronic unpredictable mild stress (CUMS)-induced myocardial ischemia and depression and b) left anterior descending coronary artery ligation (LAD) combined with chronic restraint stress (CRS)-induced myocardial ischemia and depression. We then induced exogenous corticosterone in a rat model of depressive-cardiac disease. Our study revealed that chronic administration of corticosterone could induce depression-like syndromes accompanied by cardiac insufficiency. The potential mechanism involves parallel onset of HPA axis dysfunction and an imbalance in lipid metabolism. KXS treatment successfully reversed corticosterone-induced depression-like behaviors and cardiac insufficiency. The present study highlights the pivotal role of the HPA axis and lipid metabolism in the development of comorbid depression and cardiovascular disease. Thus, KXS could be a promising therapeutic option for depressive-cardiac disease.

The rapid antidepressant effect of acupuncture on two animal models of depression by increasing the expression of synaptic proteins in the prefrontal cortex: 针刺通过增加前额叶皮层突触蛋白的表达对两种抑郁症动物模型的快速抗抑郁作用

ObjectiveTo investigate the effect of acupuncture onset time and synaptic structure in two different models of depression. MethodsA total of 150 healthy male adult SPF C57BL/6J mice were divided into five time-point groups: 1 h, 3 h, 6 h, 12 h and 24 h. Each time-point group was further divided into three groups: the model, scopolamine and acupuncture groups with 10 rats each. Rats were given forced swimming stimulation (15 min, once) before the intervention. A total of 200 healthy male adult specific pathogen-free (SPF) Sprague-Dawley (SD) rats were divided into 30 normal rats, and 170 modelling ones. A total of 90 rats were successfully modeled, and were randomly divided into three time-point groups: 1 h, 6 h and 24 h. And each time-point group was further divided into the normal, model, scopolamine, and acupuncture group. Chronic unpredictable mild stress (CUMS) combined with individual feeding was used to establish the depressed rat model. The sucrose preference test (SPT) and open field test (OFT) were used to evaluate the success of the model. There were 10 rats in each group. The acupuncture intervention was performed once for 20 min on “Baihui (GV20)”, “Yintang (GV29)”, “Hegu (LI4)”, and “Taichong (LR3)” without any other operations for the corresponding animals. Other groups were given corresponding medications. According to different time points, the forced swimming test (FST) was conducted in mice, and the FST and novelty-suppressed feeding test (NSFT) were measured in rats. Monoamine neurotransmitters (NE, DA, DOPAC, 5-HT, 5-HIAA, HVA) in the prefrontal cortex and hippocampus were detected with high performance liquid chromatography (HPLC). The expression of synapsin I, PSD95, p-mTOR, mTOR, and BDNF in the prefrontal cortex and hippocampus was determined by western blot. ResultsAt the 1 h time point, compared with the model group, the immobility time was significantly decreased in the acupuncture group (P < 0.05). At 3 h, 6 h, 12 h, and 24 h, compared with the model group, the immobility time was significantly reduced in both scopolamine and acupuncture groups (P < 0.05). At the 1 h time point, compared with the normal group, the immobility time of FST and the latency to feed were significantly increased in the model group (P < 0.05). Compared with the model group, the immobility time of FST showed a significant reduction in the acupuncture group (P < 0.05). At the 6 h and 24 h time points, compared with the normal group, the immobility time of FST and the latency to feed were significantly increased in the model group (P < 0.05). Compared with the model group, the immobility time of FST was significantly decreased in the scopolamine and acupuncture groups (P < 0.05). At the 1 h and 24 h time points, compared with the normal group, the expression levels of 5-HT, 5-HIAA, NE, DA, DOPAC, and HVA of the prefrontal cortical and hippocampal tissues were significantly reduced in the model group (P < 0.05). At the 1 h and 24 h time points, compared with the model group, the expression levels of synapsin I, PSD95, p-mTOR, and BDNF of the prefrontal cortex were significantly increased in the acupuncture group (P < 0.05). At the 1 h and 24 h time points, compared with the normal group, the expression levels of synapsin I, PSD95, p-mTOR, and BDNF of the prefrontal cortex were significantly reduced in the model group (P < 0.05). Compared with the model group, the expression levels of synapsin I, PSD95, p-mTOR, and BDNF of the prefrontal cortex were significantly increased in the acupuncture group (P < 0.05). At the 1 h and 24 h time points, compared with the normal group, the expression levels of synapsin I, PSD95, p-mTOR, and BDNF of the hippocampal tissues were significantly reduced in the model group (P < 0.05). Compared with the model group, the expression levels of synapsin I, PSD95, p-mTOR, and BDNF of the hippocampus were not significantly different in the acupuncture group (P > 0.05). ConclusionAcupuncture may play a rapid antidepressant effect by increasing the expression of synaptic plasticity proteins in the prefrontal cortex.

Effects of Astragaloside IV on Depressive Behaviour and Intestinal Flora in Post-Stroke Depressed Rat Models

Effects of Astragaloside IV on Depressive Behaviour and Intestinal Flora in Post-Stroke Depressed Rat Models

Ablated Sonic Hedgehog Signaling in the Dentate Gyrus of the Dorsal and Ventral Hippocampus Impairs Hippocampal-Dependent Memory Tasks and Emotion in a Rat Model of Depression.

Specific memory processes and emotional aberrations in depression can be attributed to the different dorsal-ventral regions of the hippocampus. However, the molecular mechanisms underlying the differential functions of the dorsal hippocampus (dHip) and ventral hippocampus (vHip) remain unclear. As Sonic Hedgehog (Shh) is involved in the dorsal-ventral patterning of the neural tube and its signaling is dysregulated by chronic unpredictable mild stress (CUMS), we investigated its role in influencing the differential functions of the dHip and vHip. Here, CUMS downregulated the expression of Shh signaling markers, including Shh and its downstream effectors GLI family zinc finger 12 (Gli1/2), Patched (Ptch), and smoothened (Smo), in both the dHip and vHip of rats, though more so in the vHip. Additionally, Shh knockdown in the dorsal or ventral dentate gyrus (DG) resulted in restrained neurogenic activity in newborn neurons, especially in immature neurons through decreased expression of Shh signaling markers. Furthermore, Shh knockdown in the DG of the dHip led to memory impairment by inhibiting experience-dependent activation of immature neurons, whereas its knockdown in the DG of the vHip led to an emotional handicap by delaying the maturation of immature neurons. Finally, Shh knockdown in either the dDG or vDG of hippocampus abolished the corresponding cognitive enhancement and emotional recovery of fluoxetine. In conclusion, Shh is essential to maintain the functional heterogeneity of dHip and vHip in depressed rat, which was mainly mediating by local changes of dependent activation and maturity of immature neurons, respectively.

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: II. Antidepressant Effect in an Experimental Animal Model.

Depression is a serious mental disorder and the most prevalent cause of disability and suicide worldwide. Quercetin (QER) demonstrated antidepressant effects in rats exhibiting anxiety and depressive-like behaviors. In an attempt to improve QER's antidepressant activity, a QER-loaded transferosome (QER-TFS) thermosensitive gel for intranasal administration was formulated and optimized. The therapeutic effectiveness of the optimized formulation was assessed in a depressed rat model by conducting a behavioral analysis. Behavioral study criteria such as immobility, swimming, climbing, sucrose intake, number of crossed lines, rearing, active interaction, and latency to feed were all considerably enhanced by intranasal treatment with the QER-TFS in situ gel in contrast to other formulations. A nasal histopathological study indicated that the QER-TFS thermosensitive gel was safe for the nasal mucosa. An immunohistochemical analysis showed that the animals treated with the QER-TFS thermosensitive gel had the lowest levels of c-fos protein expression, and brain histopathological changes in the depressed rats were alleviated. According to pharmacodynamic, immunohistochemical, and histopathological experiments, the intranasal administration of the QER-TFS thermosensitive gel substantially alleviated depressive symptoms in rats. However, extensive preclinical investigations in higher animal models are needed to anticipate its effectiveness in humans.

Current Insights into the Use of Probiotics and Fatty Acids in Alleviating Depression.

(1) Background: Depression is the most prevalent psychiatric symptom present among individuals of all ages and backgrounds, impacting an estimated 300 million people globally. Therefore, it demands a significant amount of attention when it comes to managing depression. A growing amount of data reveal that probiotics and fatty acids could be beneficial to depression. However, the opposing position maintains that they have no influence on depression. A network meta-analyses of existing datasets aid in the estimation of comparative efficacy as well as in achieving an understanding of the relative merits of different therapies. The purpose of this study was to investigate the current evidence for probiotic or fatty acid depression therapy and to establish a practical alternative for depression patients using a meta-analysis and metagenomic data from a Wistar-Kyoto (WKY) depressed rat model. (2) Methods: Probiotic data were obtained from seven randomized controlled trial studies (n = 394), and fatty acid data were obtained from 24 randomized controlled trial studies (n = 1876). Meanwhile, a metagenomics analysis of data on animal gut flora was also applied to validate the preceding evidence. (3) Results: The fatty acid studies were separated into three sections based on the duration of probiotic delivery: ≤8 weeks, 9-12 weeks, and >12 weeks. The results were as follows: for ≤8 weeks, MD = -1.65 (95% CI: -2.96--0.15), p = 0.01; for 9-12 weeks, MD = -2.22 (95% CI: -3.03--1.22), p < 0.001; for >12 weeks, MD = -1.23 (95% CI: -2.85-0.39), p = 0.14. Regarding the probiotics, the meta-analysis revealed MD = -2.19 (95% CI: -3.38--2.43), p < 0.001. The research presented herein illustrates that probiotics and fatty acids may successfully lower depression scores. Additionally, the probiotics were drastically reduced in the WKY rats. (4) Conclusions: According to the data, a depression intervention utilizing probiotics outperformed the control, implying that the use of probiotics and fatty acids may be a successful strategy for depression treatment.

Metabolomics-based alleviation of depression by Xiaoyaosan through regulation of XDH and GRIA2

BackgroundXiaoyaosan is gradually gaining acceptance and recognition within the international scientific community. However, it still lacks appropriate methodological and theoretical descriptions that adhere to modern scientific standards. The development of omics technologies, particularly metabolomics, has facilitated the characterization of body physiology and can be used to guide clinical intervention. Aim of this studyThis study explored the therapeutic mechanism of Xiaoyaosan from a metabolomics perspective. MethodsWe recruited a total of 30 patients with mild to moderate depression and 15 healthy individuals, and collected urine samples from these participants for non-targeted metabolomics analysis. To establish a depressed rat model, we used chronic unpredictable mild stress in combination with orphan, and collected urine samples from the depressed rats for untargeted metabolomics analysis. Differential metabolites (DMs) were analyzed using multivariate data methods, and the biological pathways of DMs were analyzed using MetaboAnalyst 5.0. We comprehensively analyzed the urine metabolic fingerprints of depressed patients and rats to explore common characteristics of metabolic pathways and markers. We also analyzed the key targets of Xiaoyaosan in the treatment of depression and compared them to the targets of metabolic biomarkers. Finally, we verified the regulatory effects of Xiaoyaosan on key targets using real-time quantitative PCR and Western blot. ResultsIn the treatment of depression patients with Xiaoyaosan, we identified 243 DMs and 22 metabolic pathways. For depressed rats treated with Xiaoyaosan, we found 44 DMs and 9 metabolic pathways. Our comprehensive analysis of the urinary metabolic fingerprint revealed 7 important biological pathways and 6 crucial metabolic markers in the treatment of depression with Xiaoyaosan. The key targets of Xiaoyaosan in the treatment of depression were identified as XDH and GRIA2. Real-time quantitative PCR results demonstrated that Xiaoyaosan upregulated XDH expression in the brain's prefrontal cortex and GRIA2 expression in the brain's prefrontal cortex and hippocampus of depressed rats. Western blot results indicated that Xiaoyaosan upregulated XDH expression in the hypothalamus, prefrontal cortex, and hippocampus, as well as GRIA2 expression in the prefrontal cortex and hippocampus of depressed rats. ConclusionsOur study demonstrated that Xiaoyaosan regulates the metabolic disorders of depression and plays an antidepressant role through regulation of the expression of XDH and GRIA2 in the brain tissues of CUMS rats.

Wistar-Kyoto rats and chronically stressed Wistar rats present similar depression- and anxiety-like behaviors but different corticosterone and endocannabinoid system modulation

The interplay of social, psychological, and biological stresses can trigger mental health conditions such as major depressive disorder (MDD), adjustment disorder, and posttraumatic stress disorder (PTSD). The endocannabinoid system (ECS), comprising endocannabinoids and cannabinoid receptors, is the critical pathway that mediates responses to stress stimuli. This study aimed to investigate the ECS's impact on responding to chronic social instability stress (SIS). Wistar (WIS) rats and an endogenously depressed rat model, Wistar-Kyoto (WKY), were used to evaluate depression- and anxiety-like behavioral responses, cognitive function, hormone levels, and ECS function. The animals in the stress group (WIS-STS and WKY-STS) were exposed to TMT (predator odor) for 10 mins (two exposures in total: one in light cycle and one in dark cycle) and daily roommate changes (30 days in total), while the control group (CTL) rats were exposed to a sham odor stimulus (distilled water) and did not undergo roommate changes.The results in the open field test suggest that WKY rats had significantly lower locomotor activity than WIS rats. In contrast, WKY rats and chronically stressed WIS rats presented similar depression- and anxiety-like behaviors and impaired cognitive function in the elevated plus maze, forced swimming test, and novel objective recognition test. However, chronic SIS did not exacerbate these behavioral changes in WKY rats. ELISA and Western blot analysis indicated that chronic SIS did not induce further upregulation of endocannabinoids and CB1R downregulation in WKY rats compared to WIS rats. In addition, the Luminex assay revealed that WKY rats showed a higher resilience on the HPA-axis modulation towards chronic SIS, distinguished by the hyperactivity of the HPA-axis modulation in WIS rats.Overall, the study revealed that the chronic SIS animal model (stressed WIS rats) and an animal model of endogenous depression (WKY rats) can generate similar behavioral changes in anxious behavior, behavioral despair, and cognitive impairment. Both animal models present hyperactivity of the ACTH modulation and ECS activity, while WKY rats are more resilient on CORT modulation towards chronic SIS.

Effect of chronic unpredicted mild stress-induced depression on clopidogrel pharmacokinetics in rats.

BackgroundClopidogrel is widely used to prevent and treat cardiovascular atherosclerosis and thrombosis. However, disturbance in the expression and activity of liver cytochrome metabolic enzymes significantly changes clopidogrel efficacy. Therefore, the effect of chronic unpredictable mild stress (CUMS)-induced depression on the expression of liver cytochrome metabolic enzymes and clopidogrel pharmacokinetics in rats were explored.MethodsNine different CUMSs were selected to establish a rat model of depression. Open field experiment and sucrose preference test were applied to explore the depressive behaviors. The concentration of serotonin in the cortex of depressed rats was determined using enzyme linked immunosorbent assay (ELISA). All rats were given 10 mg/kg clopidogrel orally after 12 weeks, and blood samples were collected at different time points. The clopidogrel concentration and CYP2C19/ CYP2C9 activity in rat liver microsomes were assayed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The rat liver drug enzymes expression was determined by Real-Time Quantitative Reverse Transcription PCR (RT-qPCR).ResultsOpen field experiment and sucrose preference test indicated the successful construction of the CUMS-induced depression model. The concentration of serotonin in the cortex of depressed rats decreased by 42.56% (∗∗p < 0.01). The area under the curve of clopidogrel pharmacokinetics decreased by 33.13% (∗p < 0.05) in the depression rats, while distribution volume and clearance increased significantly (∗∗p < 0.01). The half-time and distribution volume did not significantly differ. The CYP2C19 and CYP2C9 activity of liver microsomes in the CUMS-induced depression group were significantly higher than that in the control group (∗∗p < 0.01). CYP2C11 and CYP1A2 mRNA expression up-regulated approximately 1.3 - fold in the depressed rat livers compared with that in the control, whereas that of CYP2C13 was down-regulated by 27.43% (∗∗p < 0.01). CYP3A1 and CYP2C12 expression were slightly up-regulated, and that of CES1 did not change.ConclusionsThese results indicated that CUMS-induced depression altered clopidogrel pharmacokinetics, and the change in CYP450 activity and expression in depressed rat livers might contribute to the disturbance of clopidogrel pharmacokinetics.

Thymoquinone-Enriched Naringenin-Loaded Nanostructured Lipid Carrier for Brain Delivery via Nasal Route: In Vitro Prospect and In Vivo Therapeutic Efficacy for the Treatment of Depression

In the current research, a thymoquinone-enriched naringenin (NGN)-loaded nanostructured lipid carrier (NLC) was developed and delivered via the nasal route for depression. Thymoquinone (TQ) oil was used as the liquid lipid and provided synergistic effects. A TQ- and NGN-enriched NLC was developed via the ultrasonication technique and optimized using a central composite rotatable design (CCRD). The optimized NLC exhibited the following properties: droplet size, 84.17 to 86.71 nm; PDI, 0.258 to 0.271; zeta potential, −8.15 to −8.21 mV; and % EE, 87.58 to 88.21%. The in vitro drug release profile showed the supremacy of the TQ-NGN-NLC in comparison to the NGN suspension, with a cumulative drug release of 82.42 ± 1.88% from the NLC and 38.20 ± 0.82% from the drug suspension. Ex vivo permeation study displayed a 2.21-fold increase in nasal permeation of NGN from the NLC compared to the NGN suspension. DPPH study showed the better antioxidant potential of the TQ-NGN-NLC in comparison to NGN alone due to the synergistic effect of NGN and TQ oil. CLSM images revealed deeper permeation of the NGN-NLC (39.9 µm) through the nasal mucosa in comparison to the NGN suspension (20 µm). Pharmacodynamic studies, such as the forced swim test and the locomotor activity test, were assessed in the depressed rat model, which revealed the remarkable antidepressant effect of the TQ-NGN-NLC in comparison to the NGN suspension and the marketed formulation. The results signify the potential of the TQ-enriched NGN-NLC in enhancing brain delivery and the therapeutic effect of NGN for depression treatment.

Comparative study on anti-depressant effect of Zhizichi Decoction and its solid fermentation product on CUMS rats

Chronic unpredicted mild stress(CUMS) combined with isolated feeding was used to induce depressed rat model. The anti-depressant effects of Zhizichi Decoction(ZZCD) and its solid fermented product(ZZC) were analyzed by behavioral test and comparison of pathological tissues of hippocampus and liver, metabolic characteristics of intestinal flora, and relative abundance of species. The results showed that ZZC could increase sucrose preference, shorten the immobility time in the forced swim test and tail suspension test(P&lt;0.05), and repair damaged hippocampus and liver tissues, and the effect was superior to that of ZZCD. The results of Biolog ECO plates showed that the average well color development(AWCD) of intestinal flora in the model group significantly decreased and the metabolic levels of sugar and amino acids were reduced, while the AWCD of the treatment groups increased. The metabolic levels of the two carbon sources were improved in the ZZC group, while only sugar metabolic level was elevated in the ZZCD group. Metagenomic analysis of intestinal flora showed that the ratio of Firmicutes/Bacteroidetes was 3.87 in the control group, 21.77 in the model group, 5.91 in the ZZC group, and 18.48 in the ZZCD group. Lactobacillus increased by 3.28 times, and Prevotella and Bacteroidetes decreased by 75.59% and 76.39%, respectively in the model group as compared with that in the control group. Lactobacillus decreased by 31.13%, and Prevotella and Bacteroidetes increased by more than three times in the ZZC group as compared with that in the model group, while the corresponding changes in the ZZCD group were not significant. ZZC could improve depression-like beha-viors by regulating the structure of intestinal flora and metabolic functions and repairing damaged hippocampus and liver tissues in depressed rats, showing an anti-depressant effect superior to that of ZZCD. This study is expected to provide a basis for the development of new anti-depressant food products.

Hippocampal miRNA-144 Modulates Depressive-Like Behaviors in Rats by Targeting PTP1B.

BackgroundDepression is the common mental disorder in the world. However, the pathophysiology mechanism underlying depression remains elusive. It has been reported that aberrant expression of miR-144 is closely related to depression. This study was to investigate whether and how miR-144 involves in depressive-like behaviors in a chronic unpredictable mild stress (CUMS) animal model.MethodsA rat model of CUMS was established, and qRT-PCR was performed to detect the expression of miR-144 in the hippocampus of a depressed rat. The lentiviral vector carried miR-144 (LV-miR-144) was injected into the hippocampus of the CUMS rat to investigate the effects of miR-144 on the behaviors and PTP1B/TrkB/BDNF signal transduction in the hippocampus of the rat. The interaction between miR-144 and PTP1B was investigated by biological analyses and dual-luciferase reporter assay.ResultsThe results showed that CUMS rats had typical depressive behaviors, and the expression of miR-144 in the hippocampus of CUMS rats was significantly lower than that of the control group. In addition, PTP1B protein expression was significantly up-regulated, while the expression of pTrkB and BDNF protein was significantly down-regulated in the hippocampus of CUMS rats. Moreover, PTP1B was a direct target of miR-144, and miR-144 could activate the downstream TrkB/BDNF signaling pathway by inhibiting the expression of PTP1B in primary hippocampus neurons.ConclusionMiR-144 played an anti-depressive role in hippocampus dysfunction by inhibiting PTP1B and activating the TrkB/BDNF signaling pathway in the hippocampus of CUMS rats.

The Reversal Effect of Sigma-1 Receptor (S1R) Agonist, SA4503, on Atrial Fibrillation After Depression and Its Underlying Mechanism.

AimSigma-1 receptors have been investigated and shown to play a protective role in both depression and cardiovascular disease. SA4503, known as a σ1 receptor agonist, regulates cardiac calcium and potassium channels in rat models of depression. However, it remains unknown whether SA4503 can alleviate myocardial inflammation or conduction junctions in the atrium after exposure to chronic mild stress.Methods and ResultsSprague-Dawley male rats received 28-day treatment with SA4503, simultaneously with chronic mild stress. Behavior measurements were assessed after the daily doses. Additionally, a multielectrode array assessment, electrophysiological study, immunohistochemistry analysis, histological analysis, and Western blot analysis were performed. Depression rats’ hearts showed abnormal electrical activity, including disordered excitation propagation and prolonged total activation time (TAT). In addition, atrial arrhythmias (AAs), induced by burst stimulation, showed higher incidence and longer duration in the depression group compared to the control group. These changes were related to reduced conduction junctions and enhanced spatial heterogeneity. Importantly, depressed rat hearts showed greater expression of inflammatory factors (TGF-α, IL-6, and TGF-β), more collagen distribution in the extracellular matrix, and lower expression of gap junction proteins (CX40 and CX43). Furthermore, SA4503 partially mitigated the above indices in the depression group (P < 0.01 for all groups).ConclusionThese findings show the effects of the σ1R agonist SA4503; it alleviates atrial myocardial inflammation and conduction junctions after chronic mild stress. SA4503 may be the promising pharmacological agent to treat depression-related AAs by increasing conduction function, improving the expression of connexin 40 and 43, and reducing cardiac myocardial inflammation.

In vitro and in vivo metabolism of Cistanche tubulosa extract in normal and chronic unpredictable stress-induced depressive rats

Cistanche tubulosa, one species of Cistanches Herba, was recently confirmed to have antidepressant efficacy in chronic unpredictable stress (CUS) rats by restoring homeostasis of intestinal microbiota. In this paper, we aim to explore the metabolic profile of C. tubulosa in normal and CUS induced depressive model rats in vitro and in vivo. Using UPLC-Q-TOF-MS, the in vitro gastrointestinal metabolism of Cistanche tubulosa extract (CTE) was evaluated in both normal and CUS rats. At the same time, in vivo metabolism of CTE in normal and depressed rats were also investigated in rat urine and feces. A total of 20 and 26 metabolites were characterized from in vitro and in vivo metabolism in normal and CUS rats, respectively. CTE was metabolized to aglycones and degradation products of phenylethanoid glycosides (PhGs) and iridoid glycosides whether by normal or depressed rat intestinal microbiota in vitro. Phase II metabolites of aglycones and degradation products of PhGs and iridoid glycosides were the main metabolites in rat urine and feces. Additionally, the metabolic capability to generate secondary glycosides and aglycones in depressive rat intestinal microbiota was much weaker than that in normal rat intestinal microbiota, which was attributed to the disordered glycoside hydrolases produced by intestinal microbiota in CUS depressed rats. The results of this study laid the foundation for understanding the metabolic process and therapeutic mechanism of CTE's antidepressant property.

Unfolded protein response and associated alterations in toll-like receptor expression and interaction in the hippocampus of restraint rats

Recent evidence suggests that the cellular response to stress often elicits the unfolded protein response (UPR), which has an active role in major depression in emotionally relevant regions of the brain, such as the hippocampus. Much of the UPR activity has been found to be coalesced with the pro-inflammatory environment of the depressed brain. Specifically, downstream transcriptions of pro-inflammatory cytokines and increased regulation of candidate inflammatory mediators, such as toll-like receptors (TLRs), are promoted by the UPR. The present study examined the hippocampus associated expression profile of Tlr genes and their interaction with the UPR chaperone GRP94 in stress-induced rodent model of depression (restraint stress model). Also, the expression status of UPR related genes was evaluated in hippocampus using the same model. mRNA and protein levels of Tlr and UPR associated genes were examined by qRT-PCR and Western blot, respectively. Co-immunoprecipitation (Co-IP) method was used to determine the direct interaction between TLRs with GRP94 in depressed rat brain. The results showed that both UPR (Xbp-1, its spliced variant sXbp-1, Atf-6, Chop, and Grp94) and Tlr (2, 3, 4, 7 and 9) genes were significantly upregulated in the hippocampi of rats who were exposed to restraint stress. Similar upregulation was observed in the protein levels of the above-mentioned TLRs and the UPR chaperone protein GRP94 as well as total and phosphorylated forms of sensor proteins IRE1α and PERK. Further, a significantly increased interaction was observed between GRP94 and the activated TLR proteins. Since, increased inflammatory activity in vulnerable areas like hippocampus is coherently associated with depressed brain; our present data suggest that the UPR may be an integral part of increased activity of inflammatory regulations in depression.

Regulation of the kynurenine metabolism pathway by Xiaoyao San and the underlying effect in the hippocampus of the depressed rat

Ethnopharmacological relevanceXiaoyao San (XYS) is a classic Chinese herbal formula for treatment of depression. The present study aimed to investigate the antidepressant effects of XYS in a rat model of chronic unpredictable mild stress (CUMS) and the underlying mechanisms. Materials and methodsA CUMS rat model of depression was established via 4 weeks of unpredictable stimulation. Then the rats were orally administered paroxetine and XYS for 2 weeks with continued stress. Behavioral assessments, including an open field test (OFT), sucrose preference test (SPT) and forced swim test (FST), were conducted to evaluate the antidepressant effects of XYS. The concentrations in rat plasma of tryptophan (Trp) and its metabolic products, including kynurenine (Kyn) and quinolinic acid (QUIN), were determined using high performance liquid chromatography tandem mass spectrometry with electrochemical detection (HPLC-MS/MS). The mRNA and protein levels in rat hippocampus of depression-related brain derived neurotrophic factor (BDNF), cyclic AMP response element binding protein (CREB) and nerve cell adhesion molecule (NCAM) were determined by real-time qPCR and Western blot, respectively. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the activities of indoleamine 2,3-dioxygenase (IDO) and kynurenine-3-monooxygenase (KMO) in rat plasma. ResultsThe results showed that a successful CUMS rat model was established through 4 weeks of continuous unpredictable stimulation, as indicated by the significant decrease in locomotor activity and increase in immobility time in the OFT, reduction in body weight and food intake etc. Compared with the normal group, the concentrations of Kyn and QUIN had significantly (p < 0.05) decreased at day 28 in the control group, but then improved after drug treatment with paroxetine and XYS. There were no obvious changes in the activities of IDO and KMO. Compared with the normal group, the mRNA of NCAM, CREB and BDNF were significantly down-regulated (p < 0.001) in the control group, BDNF gene was up-regulated by paroxetine or XYS treatment, NCAM and CREB gene did not change in XYS group, protein expressions of BDNF and CREB were significantly increased, and NCAM was significantly reduced (p < 0.05). ConclusionsXYS reversed the abnormalities of the tryptophan-kynurenine metabolic pathways in depressed rats and achieved an excellent antidepressant effect. Its direct impact may be observed as changes in biological indicators in rat hippocampus tissue.

Abnormal levels of seven amino neurotransmitters in depressed rat brain and determination by HPLC-FLD.

The determination of amino acids with actions like neurotransmitters or modulators has been increasingly important for diagnosis in many neuropsychiatric diseases. A rapid and simple high-performance liquid chromatography with fluorescence detection method was developed for simultaneous determination of seven amino acids: aspartate (Asp), glutamate (Glu), serine (Ser), glutamine (Gln), glycine (Gly), taurine (Tau) and γ-aminobutyric` acid (GABA). Homoserine was used as an internal standard. The analysis was performed on a BDS column with methanol and 50 mm sodium acetate solution (pH 6.5) using a simple gradient elution. Several parameters of the developed method were validated including linearity, accuracy, precision, extraction recovery and stability, which were within the acceptable range. The method was successfully applied to determination of real samples: hippocampus and cortex in depressed rats exposed to chronically unpredictable stress in order to study if there existed differences in the seven amino acids levels between depressed rats and control. The results showed that Asp, Gly, Tau and GABA significantly decreased with increasing Gln in the hippocampus of depressed rats, compared with that of the control group, among which obviously lower level of Asp and higher level of Gln in cortex were observed. The analytical method and the results could be useful for clinical diagnosis and further insight into pathophysiological mechanism of depression.

Effect of Cynomorium total flavone on depression model of perimenopausal rat.

PurposeTo observe the effect of cynomorium total flavone on the depression model of perimenopausal rat and to analyze the action characteristics of cynomorium total flavone on depression of rat with perimenopausal syndrome.MethodDuplicate the model of rat with perimenopausal depression based on the combined method of incomplete castration and chronic stimulation, and keep drug administration for 35d. And then measure related behavior indicators and the change of biochemical index level in serum and brains; measure the estrogen/androgen receptor (ER/AR) in related tissues and the ERmRNA expression in hypothalamus.ResultIt can be seen that cynomorium total flavone can significantly improve the behavior indicators of rat with perimenopausal depression; obviously or significantly change the level of related biomedical indexes in serum and brains of perimenopausal depressed rat; obviously or significantly increase the expression of ER/AR in related tissues of perimenopausal depressed rat; obviously or significantly increase the ERmRNA expression in hypothalamus.ConclusionCynomorium total flavone can adjust hypothalamic-pituitary-gonadal axis by increasing E2, and make related biomedical indexes and hormone receptors tend to be normal, so as to relieve perimenopausal syndrome and perimenopausal syndrome with depression.

Ethanol consumption in the Sprague–Dawley rat increases sensitivity of the dorsal raphe nucleus to 5,7-dihydroxytryptamine

Alcoholism afflicts 1 in 13 US adults, and comorbidity with depression is common. Levels of serotonin (5-HT) metabolites in alcoholic or depressed humans and rat strains are lower compared to healthy counterparts. Rats bred for ethanol (EtOH) preference are common in EtOH studies, however out-bred strains better model the range of EtOH consumption in humans. We examined voluntary EtOH consumption in out-bred Sprague–Dawley (SD) rats placed in the 20% EtOH intermittent access drinking paradigm (IA). Acquisition of 20% EtOH consumption (g EtOH/kg/24h) was assessed during the first 6–8 weeks of IA. Rats naturally separated into two groups (Drinkers or Non-drinkers) based on EtOH intake above or below 0.5g/kg/24h prior to treatment intervention. We examined the effect of central 5-HT depletion on EtOH consumption by infusing 5,7-dihyroxytryptamine (5,7-DHT; i.c.v., 200–300μg) or vehicle and measured EtOH consumption for 4 weeks post-operatively in IA. Compared to baseline, there was no effect of vehicle or 5,7-DHT on EtOH consumption during the post-operative period. Quantification of 5-HT depletion in the dorsal raphe nucleus (DRN) using tryptophan hydroxylase-2 (TPH2) immunohistochemistry resulted in a 76% decrease in staining with 5,7-DHT treatment. Interestingly, preservation of the ventromedial (VM) sub-regions was evident in all animals treated with 5,7-DHT, regardless of drinking behavior. In addition, Drinkers treated with 5,7-DHT had significantly more TPH2 depletion in the DRN compared to Non-drinkers. Our findings indicate that out-bred SD rats exhibit a natural EtOH consumption behavior (Drinker or Non-drinker) that is stable across time and independent of 5-HT depletion in the CNS. In addition, rats that regularly consumed >0.5g EtOH/kg had greater sensitivity to 5,7-DHT in the DRN, indicating an interaction between EtOH and sensitivity of DRN 5-HT cells to neurotoxic substances. This may contribute to the dysfunctionality of the 5-HT system in alcoholic humans and lead to a better understanding of current pharmacological treatments for this addiction.

Alterations of amino Acid level in depressed rat brain.

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats' brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats' brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats' brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and γ-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-α-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, γ-amino-n-butyric acid and L-α-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.