Effects of Refined Xiaoyaosan on Depressive-Like Behaviors in Rats with Chronic Unpredictable Mild Stress through Neurosteroids, Their Synthesis and Metabolic Enzymes

Preclinical evidence evaluation of Xiaoyao san in treating chronic unpredictable mild stress model of depression based on meta-analysis

BACKGROUND

In view of the current challenges in the treatment of depression, in order to improve the efficacy and avoid adverse reactions, people pay attention to the treatment of traditional Chinese medicine. Xiaoyao san is a classic prescription commonly used in the treatment of depression, with the role of harmonizing liver and spleen, and shows great potential in the treatment of depression.

PURPOSE

The purpose of this study is to comprehensively evaluate the efficacy and specific mechanism of Xiaoyao san in the treatment of chronic unpredictable mild stress (CUMS) model of depression through systematic evaluation and meta-analysis, so as to provide strong preclinical evidence for the clinical treatment of Xiaoyao san and provide a new strategy for the development of antidepressants.

METHODS

The preclinical literature published before March 2023 was searched in Cochrane Library, PubMed, Web of Science, EMbase, CNKI, VMIS, Wan-Fang, and CBM and other database systems. Stata15 was used for overall effect analysis and subgroup analysis, and summarized the potential mechanism of action.

RESULTS

A total of 25 studies were included, involving 569 animals. The average score of methodological quality was 7.48/10. Meta-analysis shows that Xiaoyao san can effectively improve food intake and body weight, restore sucrose consumption, reduce the immobility time in forced swimming, and increase the total exercise distance, grid crossing and upright times in the open field experiment. Its therapeutic effect is closely related to improving the abnormal activation of Hypothalamic-pituitary-adrenal axis and inhibiting the expression of glutamate.

CONCLUSION

To sum up, in CUMS animal model, Xiaoyao san can significantly improve the symptoms of depression, restore the lost pleasure behavior and curiosity about the new environment, relieve tension and anxiety, and improve the occurrence of depression in many ways, which may be a new treatment strategy for CUMS model of depression.

Profiling of adrenal corticosteroids in blood and local tissues of mice during chronic stress

Stress increases plasma concentrations of corticosteroids, however, their tissue levels are unclear. Using a repeated social defeat paradigm, we examined the impact of chronic stress on tissue levels of corticosterone (CORT), progesterone (PROG), 11-deoxycorticosterone (11DOC) and 11-dehydrocorticosterone (11DHC) and on gut microbiota, which may reshape the stress response. Male BALB/c mice, liquid chromatography-tandem mass spectrometry and 16S RNA gene sequencing were used to screen steroid levels and fecal microbiome, respectively. Stress induced greater increase of CORT in the brain, liver, and kidney than in the colon and lymphoid organs, whereas 11DHC was the highest in the colon, liver and kidney and much lower in the brain and lymphoid organs. The CORT/11DHC ratio in plasma was similar to the brain but much lower in other organs. Stress also altered tissue levels of PROG and 11DOC and the PROG/11DOC ratio was much higher in lymphoid organs that in plasma and other organs. Stress impacted the β- but not the α-diversity of the gut microbiota and LEfSe analysis revealed several biomarkers associated with stress treatment. Our data indicate that social defeat stress modulates gut microbiota diversity and induces tissue-dependent changes in local levels of corticosteroids, which often do not reflect their systemic levels.

Xiaoyaosan ameliorates depressive-like behavior and susceptibility to glucose intolerance in rat: involvement of LepR-STAT3/PI3K pathway in hypothalamic arcuate nucleus

BACKGROUND

Accumulating evidence has demonstrated that arcuate nucleus (ARC) of the hypothalamus is likely responsible for the close association between chronic stress, depression, and diabetes. Xiaoyaosan (XYS), a Chinese herbal formula, remarkably improves depressive-like behavior and glucose intolerance, but the mechanism remains unclear. Leptin receptor (LepR) regulates energy expenditure and depression by mediating the action of leptin on the ARC. Therefore, we hypothesized that XYS may regulate depressive-like behavior and glucose intolerance via the leptin and its cascade LepR-STAT3/PI3K pathway in the ARC.

METHODS

A rat model of depressive-like behavior and susceptibility to glucose intolerance was induced by exposure to chronic unpredictable mild stress (CUMS) for six weeks. XYS (2.224 g/kg) was orally gavaged for six weeks, and fluoxetine (2.0 mg/kg) was administrated to the positive control group. Depressive-like behaviors were assessed using the open field test (OFT), sucrose preference test (SPT) and forced swim test (FST). Fasting blood glucose (FBG) and oral glucose tolerance test (OGTT) were performed to evaluate the effects of XYS on blood glucose. Peripheral leptin and blood lipids were detected using enzyme-linked immunosorbent assay and an automatic biochemical analyzer, respectively. The effects of XYS on the LepR-STAT3/PI3K pathway were detected by quantitative real-time PCR and western blotting.

RESULTS

XYS ameliorated CUMS-induced depressive-like behaviors and elevated blood glucose. XYS improved the food intake but have no significant effects on the body weight. Peripheral leptin and its central receptor were also suppressed by XYS, accompanied by the downregulation of JAK2/STAT3 and PI3K/AKT pathway in the ARC. Additionally, XYS increased AGRP and NPY expression but inhibited POMC in the ARC.

CONCLUSIONS

XYS improves depressive-like behaviors and susceptibility to glucose intolerance induced by CUMS, which may be achieved by the downregulation of the LepR-STAT3/PI3K signaling pathway in the ARC.

Depression with obstructive sleep apnea lead to high cardiovascular disease morbidity/all-cause mortality: Findings from the SHHS cohort

The aim of this study is to explore the association between depression and obstructive sleep apnea, and cardiovascular disease morbidity/all-cause mortality using Sleep Heart Health Study data. This post hoc analysis of a prospective study used patient data from the Sleep Heart Health Study conducted between 1995 and 1998. The association between depression and obstructive sleep apnea, and cardiovascular disease morbidity/all-cause mortality was explored using multivariable Cox proportional hazard models. A total of 4918 participants, 656 (13.3%) with obstructive sleep apnea (obstructive sleep apnea group), 1614 (32.8%) with depression (depression group), 482 (9.8%) with depression and obstructive sleep apnea (depression and obstructive sleep apnea group), and 2166 (44%) with neither obstructive sleep apnea nor depression (health group), were included. The incidence of cardiovascular disease was 24.5%, 31.0%, 31.6% and 41.7% for healthy, depression, obstructive sleep apnea, and depression and obstructive sleep apnea groups, respectively. The risk of cardiovascular disease in depression and obstructive sleep apnea participants was increased compared with that in healthy participants, which was consistent across various definitions of obstructive sleep apnea (hazard ratio [95% confidence interval]: 1.24 [1.06-1.47]; 1.25 [1.05-1.49]; 1.28 [1.06-1.54]; 1.55 [1.22-1.96] for apnea-hypopnea index ≥ 10 per hr, 15 per hr, 20 per hr, 30 per hr, respectively). The risk of all-cause mortality was increased in the depression and obstructive sleep apnea participants (hazard ratio: 1.46; 95% confidence interval: 1.07-1.99) compared with that in healthy participants when the definition of obstructive sleep apnea was apnea-hypopnea index ≥ 30. Participants with depression and obstructive sleep apnea might be at a greater risk of cardiovascular disease, and those with higher apnea-hypopnea index might be at a greater risk of all-cause mortality.

Antidepressant effects of the traditional Chinese herbal formula Xiao-Yao-San and its bioactive ingredients

BACKGROUND

Depression is one of the most debilitating and severe psychiatric disorders and a serious public health concern. Currently, many treatments are indicated for depression, including traditional Chinese medicinal formulae such as Xiao-Yao-San (XYS), which has effective antidepressant effects in clinical and animal studies.

PURPOSE

To summarize current evidence of XYS in terms of the preclinical and clinical studies and to identify the multi-level, multi-approach, and multi-target potential antidepressant mechanisms of XYS and active components of XYS by a comprehensive search of the related electronic databases.

METHODS

The following electronic databases were searched from the beginning to April 2022: PubMed, MEDLINE, Web of Science, Google Scholar, and China National Knowledge Infrastructure.

RESULTS

This review summarizes the antidepressant mechanisms of XYS and its active ingredients, which are reportedly correlated with monoamine neurotransmitter regulation, synaptic plasticity, and hypothalamic-pituitary-adrenal axis, etc. CONCLUSION: XYS plays a critical role in the treatment of depression by the regulation of several factors, including the monoaminergic systems, hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, brain-gut axis, and other pathways. However, more clinical and animal studies should be conducted to further investigate the antidepressant function of XYS and provide more evidence and recommendations for its clinical application. Our review provides an overview of XYS and guidance for future research direction.

Integrated network pharmacology and hepatic metabolomics to reveal the mechanism of Acanthopanax senticosus against major depressive disorder

Objective:Acanthopanax senticosus (Rupr. et Maxim.) Harms (ASH) is a traditional herbal medicine widely known for its antifatigue and antistress effects, as well as tonifying qi, invigorating spleen and kidney, and tranquilizing the mind. Recent evidence suggests that ASH has a therapeutic effect on major depressive disorder (MDD), but its mechanism is still unclear. The current study aimed to investigate the effect of ASH on MDD and potential therapeutic mechanisms.

Materials and Methods: The chemical compound potential target network was predicted based on network pharmacology. Simultaneously, chronic unpredictable mild stress (CUMS) model mice were orally administrated ASH with three dosages (400, 200, and 100 mg/kg) for 6 weeks, and hepatic metabolomics based on gas chromatography–mass spectrometry (GC–MS) was carried out to identify differential metabolites and related metabolic pathways. Next, the integrated analysis of metabolomics and network pharmacology was applied to find the key target. Finally, molecular docking technology was employed to define the combination of the key target and the corresponding compounds.

Results: A total of 13 metabolites and four related metabolic pathways were found in metabolomics analysis. From the combined analysis of network pharmacology and metabolomics, six targets (DAO, MAOA, MAOB, GAA, HK1, and PYGM) are the overlapping targets and two metabolic pathways (glycine, serine, and threonine metabolism and starch and sucrose metabolism) are the most related pathways. Finally, DAO, MAOA, MAOB, GAA, HK1, and PYGM were verified bounding well to their corresponding compounds including isofraxidin, eleutheroside B1, eleutheroside C, quercetin, kaempferol, and acacetin.

Conclusion: Based on these results, it was implied that the potential mechanism of ASH on MDD was related to the regulation of metabolism of several excitatory amino acids and carbohydrates, as well as the expression of DAO, MAOA, MAOB, GAA, HK1, and PYGM.

Research progress on classical traditional chinese medicine formula xiaoyaosan in the treatment of depression

Depression is an emotional disorder that is problematic in psychiatry owing to its unclear etiology and unknown pathogenesis. Traditional Chinese medicine formulations such as Xiaoyaosan have been widely used throughout history to treat depression. In this review, we have focused on recent evidences elucidating the links between Xiaoyaosan and the treatment of depression. Data from animal and clinical studies, focusing on the pharmacological mechanisms, clinical applications, and effective materials that form the basis for the treatment of depression are presented and discussed. We found that the antidepressant effects of Xiaoyaosan are related to the effects of monoamine neurotransmitters, regulation of the hypothalamic-pituitary-adrenal axis, neuroplasticity, synaptic plasticity, inflammatory response, neuroprotection, brain-gut axis, regulation of intestinal microbiota, oxidative stress, and autophagy for reducing neuronal apoptosis. This review highlights the current evidence supporting the use of Xiaoyaosan as an antidepressant and provides an overview of the potential mechanisms involved.

Identification of absorbed compounds of Xiao Yao San Jia Wei and pharmacokinetic study in depressed rats by force swimming stress

Xiao-Yao-San-Jia-Wei (XYSJW) is a commonly prescribed formulation for depression and anorexia in the Jiang Su Province Hospital of Chinese Medicine. Unfortunately, the proper dosage of this formulation is still unclear due to its limited chemical and pharmacokinetic profiles. Thus, in the present study, a sensitive, precise, and rapid procedure for the identification of absorbed compounds (Cs) in the plasma of depressed rats together with a pharmacokinetic analysis was established with the help of ultra-flow liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UFLC-Q-TOF MS/MS) and ultra-flow liquid chromatography coupled with electrospray ionization triple quadrupole tandem mass spectrometry (UFLC-QQQ MS/MS). Based on the characteristic fragmentation, neutral loss, mass defect filter, relevant literature and reference standards, 225 Cs in the XYSJW extract and 20 Cs in the plasma of the depressed rats were tentatively recognized via UFLC-Q-TOF MS/MS and UFLC-QQQ MS/MS. Then, the 12 major absorbed Cs in the depressed rats after oral XYSJW administration were chosen to further investigate its pharmacokinetic profile by UFLC-QQQ MS/MS. This study provides a systematic approach for the rapid and qualitative analysis of absorbed Cs in depressed rats and investigating the pharmacokinetics of XYSJW. More importantly, our work provides key information on the chemical and pharmacokinetic profiles of XYSJW in vitro and in vivo, which may benefit its therapeutic efficacy and further pharmacological studies involving this formulation.

Xiao-Yao-San-Jia-Wei (XYSJW) is a commonly prescribed formulation for depression and anorexia in the Jiang Su Province Hospital of Chinese Medicine.

A preliminary study on the mechanism of the neurosteroid-mediated ionotropic receptor dysfunction in neurodevelopmental toxicity induced by decabromodiphenyl ether

The mechanism of neurodevelopmental toxicity of decabromodiphenyl ether (BDE209) remains unclear. Recent evidence suggests that neurosteroids disorders play a vital role in BDE209 induced-neurodevelopmental toxicity. To explore the mechanism of it, pregnant ICR mice were orally gavaged with 0, 225, and 900 mg kg^-1 BDE209 for about 42 days. Spatial learning and memory abilities of offspring were tested on postnatal day (PND) 21. Offspring were euthanized at PND26, the neuronal structure, neurosteroids level, and related proteins including neurosteroids synthase, ionotropic receptors and cAMP-response element binding protein (CREB) pathway were evaluated, as well as Ca²⁺ concentration and the mitochondrial membrane potential (Mmp). Our results showed that BDE209 impaired learning and memory abilities and disrupted neuronal structure. Meanwhile, BDE209 decreased the pregnenolone (PREG), dehydroepiandrosterone (DHEA), progesterone (PROG) and allopregnanolone (ALLO) levels in the serum and brain, as well as the mRNA and protein levels of cholesterol-side-chain cleavage enzyme (P450scc), steroid 17α-hy-droxylase (P450C17), 3β-hydroxysteroid dehydrogenase (3β-HSD) and steroid 5α-reductase of type I (5α-R) in the hippocampi. Also, BDE209 suppressed mRNA and protein levels of NR1, NR2A and NR2B subunits of the N-methyl-D-aspartic acid receptor (NMDAR) and α1 subunit of the Gamma-amino butyric acid A receptor (GABAAR), but increased the levels of β2 and γ2 subunits of the GABAAR in the hippocampi. Moreover, BDE209 increased the Ca²⁺ concentration and phosphorylation extracellular regulated protein kinases (P-ERK) 1/2 level, but decreased the P-CREB and Mmp level in the hippocampi. These results indicate that BDE209 exposure during pregnancy and lactation is possible to affect learning and memory formation of offspring by the neurosteroid-mediated ionotropic receptors dysfunction.

Serum metabolomics reveals compatibility rules of the antidepressant effects of Xiaoyaosan and its efficacy groups

Traditional Chinese medicines (TCMs) have attracted more attentions in the treatment of depression. Xiaoyaosan (XYS), a classic anti-depression TCM prescription, contains eight herbs. However, the compatibility effects of XYS in modern pharmacology need to be investigated in depth. In this study, the chronic unpredictable mild stress (CUMS) depression-like model was constructed. Afterwards, XYS was divided into the Shugan and the Jianpi groups according to the research strategy ofefficacy groups. Meanwhile, a proton nuclear magnetic resonance spectrometry (¹H NMR) based serum metabolomics was applied. XYS and its efficacy groups significantly regulated the abnormal levels of differential metabolites related to depression, but to different degrees. Metabolic profiling by orthogonal partial least squares discriminant analysis showed that XYS at high dose (XH) exhibited the strongest effects than other treatment groups. Ten metabolites related to depression were identified as differential metabolites. Besides, relative distance (R_d) was calculated to quantitatively evaluate the effects. We found that XH group had the highest R_d value. Moreover, among the five metabolic pathways of depression, XYS and Jianpi groups significantly regulated all pathways while Shugan group regulated four pathways. These findings lay a solid foundation for comprehensively and deeply understanding the compatibility effects of XYS against depression.

Xiaoyaosan Improves Antibiotic-Induced Depressive-Like and Anxiety-Like Behavior in Mice Through Modulating the Gut Microbiota and Regulating the NLRP3 Inflammasome in the Colon

Disturbance of the gut microbiota plays an essential role in mental disorders such as depression and anxiety. Xiaoyaosan, a traditional Chinese medicine formula, has a wide therapeutic spectrum and is used especially in the management of depression and anxiety. In this study, we used an antibiotic-induced microbiome-depleted (AIMD) mouse model to determine the possible relationship between imbalance of the intestinal flora and behavioral abnormalities in rodents. We explored the regulatory effect of Xiaoyaosan on the intestinal flora and attempted to elucidate the potential mechanism of behavioral improvement. We screened NLRP3, ASC, and CASPASE-1 as target genes based on the changes in gut microbiota and explored the effect of Xiaoyaosan on the colonic NLRP3 pathway. After Xiaoyaosan intervention, AIMD mice showed a change in body weight and an improvement in depressive and anxious behaviors. Moreover, the gut flora diversity was significantly improved. Xiaoyaosan increased the abundance of Lachnospiraceae in AIMD mice and decreased that of Bacteroidaceae, the main lipopolysaccharide (LPS)-producing bacteria, resulting in decreased levels of LPS in feces, blood, and colon tissue. Moreover, serum levels of the inflammatory factor, IL-1β, and the levels of NLRP3, ASC, and CASPASE-1 mRNA and DNA in the colon were significantly reduced. Therefore, Xiaoyaosan may alleviate anxiety and depression by modulating the gut microbiota, correcting excessive LPS release, and inhibiting the immoderate activation of the NLRP3 inflammasome in the colon.

Analysis of Antidepressant Activity of Huang-Lian Jie-Du Decoction Through Network Pharmacology and Metabolomics

Depressive disorder is a common mental disorder characterized by depressed mood and loss of interest or pleasure. As the Herbal medicines are mainly used as complementary and alternative therapy for depression. This study aimed at exploring antidepressant activity of Huang-lian Jie-du Decoction (HLJDD), and evaluating active components and potential depression-associated targets. HLJDD was administered on chronic unpredictable mild stress-induced (CUMS) depressive mice. Behavior evaluation was performed through force swimming test (FST), novelty-suppressed feeding test (NSF), and open field test (OFT). Active components of HLJDD, potential targets, and metabolic pathways involved in depression were explored through systemic biology-based network pharmacology assay, molecular docking and metabonomics. FST assay showed that CUMS mice administered with HLJDD had significantly shorter immobility time compared with control mice. Further, HLJDD alleviated feeding latency of CUMS mice in NSFand increased moving distance and duration in OFT. In the following network pharmacology assay, thirty-eight active compounds in HLJDD were identified based on drug-like characteristics, and pharmacokinetics and pharmacodynamics profiles. Moreover, forty-eight molecular targets and ten biochemical pathways were uncovered through molecular docking and metabonomics. GRIN2B, DRD, PRKCA, HTR, MAOA, SLC6A4, GRIN2A, and CACNA1A are implicated in inhibition of depressive symptoms through modulating tryptophan metabolism, serotonergic and dopaminergic synaptic activities, cAMP signaling pathway, and calcium signaling pathway. Further network pharmacology-based analysis showed a correlation between HLJDD and tryptophan metabolism. A total of thirty-seven active compounds, seventy-six targets, and sixteen biochemical pathways were involved in tryptophan metabolism. These findings show that HLJDD acts on potential targets such as SLC6A4, HTR, INS, MAO, CAT, and FoxO, PI3K/Akt, calcium, HIF-1, and mTOR signaling pathways, and modulates serotoninergic and dopaminergic synaptic functions. In addition, metabonomics showed that tryptophan metabolism is the primary target for HLJDD in CUMS mice. The findings of the study show that HLJDD exhibited antidepressant effects. SLC6A4 and MAOA in tryptophan metabolism were modulated by berberine, baicalein, tetrahydroberberine, candicine and may be the main antidepressant targets for HLJDD.

Rapid Eye Movement Sleep Deprivation Combined With Fluoxetine Protects Against Depression-Induced Damage and Apoptosis in Rat Hippocampi via A1 Adenosine Receptor

Background: Rapid eye movement sleep deprivation (REMSD) and fluoxetine affect depression, yet the detailed molecular mechanisms were not clear. Methods: Rat depression chronic unpredictable stress was constructed, and the body weight of rats was measured. The efficacy of REMSD and fluoxetine on the pleasure experience, exploration, and cognition of rats with depression was determined by the Sucrose preference test, the open field test, and Morris water task, respectively. The effects of REMSD and fluoxetine on depression-induced damage and apoptosis in rat hippocampi were detected using hematoxylin-eosin staining and terminal transferase-mediated biotin 2'-deoxyuridine, 5'-triphosphate nick end labeling. A1 adenosine receptor content was measured by immunohistochemistry. Relative expressions of the A1 adenosine receptor, proteins related to apoptosis (B Bcl-2-associated X protein; B-cell lymphoma 2), phosphoinositide 3-kinase, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific two were quantified by quantitative real-time polymerase chain reaction and Western blot as needed. Results: Depression decreased rat weight. REMSD combined with fluoxetine increased body weight, prompted rat behavior, alleviated depression-induced damage, attenuated apoptosis, and promoted A1 adenosine receptor level in rat hippocampi. Furthermore, the combined therapy upregulated expressions of A1 adenosine receptor, B-cell lymphoma 2, and phosphoinositide 3-kinase but downregulated those of B-cell lymphoma 2-associated X protein, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific 2 in the hippocampi of rats with depression. Conclusion:REMSD combined with fluoxetine protected rats against depression-induced damage and apoptosis in the hippocampus via the A1 adenosine receptor, providing a possible treatment strategy for depression.

Metabolomics analysis of the antidepressant prescription Danzhi Xiaoyao Powder in a rat model of Chronic Unpredictable Mild Stress (CUMS)

ETHNOPHARMACOLOGICAL RELEVANCE

Danzhi Xiaoyao Powder (DZXY) is a classical prescription, that has been extensively used in traditional Chinese medicine (TMC) to treat depression for many years. However, the mechanism of DZXY is still unclear.

AIM OF THE STUDY

The aim was to investigate the mechanism of the antidepressant effect of DZXY on a rat model of chronic unpredictable mild stress (CUMS).

MATERIALS AND METHODS

Forty male SD (Sprague-Dawley) rats with similar open field test (OFT) results were randomLy divided into a control group (n = 10) and an experimental group (n = 30). A depression model was established in the experimental group using the CUMS method. After the CUMS model was established successfully, the rats were randomLy divided into a depression model group and a DZXY group. The DZXY group was fed DZXY, while the depression model group and control group were given an equal amount of 0.5% sodium carboxymethyl cellulose suspension. Intragastric administration was performed once daily for 14 consecutive days. Animal weight, the sugar preference test, the open field test and the forced swimming test were used to evaluate the modeling effect and the antidepressant effect of DZXY. After the experiment, the plasma of rats was collected and the changes in plasma metabolites were analyzed by UPLC/Q-TOF-MS. The UPLC/Q-TOF-MS spectra data were evaluated by pattern recognition analysis to determine the changes in endogenous metabolites in the rat plasma samples.

RESULTS

The results of the behavioral investigation showed that the rat model of depression was successfully replicated and that DZXY had an antidepressant effect. Using the UPLC-MS/MS metabolomics platform, partial least squares (PLS) and orthogonal partial least squares (OPLS), metabolic profile models (R2 and Q2 ≥ 0.5) of rat plasma were successfully constructed. The model could distinguish among the control group, the depression model group and the DZXY group. Finally, 38 differential metabolites were identified in the plasma. According to KEGG (http://www.kegg.jp) pathway analysis, amino acid metabolism, lipid metabolism, purine metabolism, the prolactin signaling pathway and bile secretion were enriched and represented the main metabolic pathways influenced in the plasma.

CONCLUSIONS

This study successfully established a CUMS depression model. A total of 38 differential metabolites associated with depression were identified in the plasma of rats, 24 of which were modulated by DZXY. These results suggest that DZXY can improve excitability and play an antidepressant role by regulating phenylalanine metabolism, arachidonic acid metabolism, porphyrin metabolism, D-arginine and D-ornithine metabolism, steroid hormone biosynthesis, unsaturated fatty acid biosynthesis and steroid biosynthesis.

Effect of Xiaoyaosan on Colon Morphology and Intestinal Permeability in Rats With Chronic Unpredictable Mild Stress

Purpose

In our present study, a rat depression model induced by 6 weeks of chronic unpredictable mild stress (CUMS) was established, and we investigated how Xiaoyaosan affects the intestinal permeability of depressed rats and alterations in tight-junction proteins (TJs) involved in this process.

Methods

The rat depression model was established using CUMS for 6 consecutive weeks. A total of 40 healthy male Sprague-Dawley rats were randomly sorted into four groups: the control group, CUMS group, Xiaoyaosan group, and fluoxetine group. All groups, excluding the control group, were subjected to the 6-week CUMS program to generate the depression model. Body weight, food intake, and behaviors were observed during the modeling period. Histopathological alterations of colon tissue were evaluated by hematoxylin-eosin staining (H&E), and mucus-containing goblet cells were detected by periodic acid-Schiff (PAS) staining. The ultrastructural morphology of colonic mucosa was observed by transmission electron microscopy. Furthermore, immunohistochemistry (IHC) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to determine the expression of TJs. The concentrations of 5-hydroxytryptamine (5-HT) in the hypothalamus and colon were also assessed using enzyme-linked immunosorbent assay (ELISA).

Results

Treatment of depressed rats with Xiaoyaosan alleviated depression-like behaviors as demonstrated by increases in the total distance traveled, the number of entries into the central area in the open field test, the duration spent in the central area, and sucrose preference. Xiaoyaosan treatment also increased body weight gain and food intake in depressed rats. Moreover, Xiaoyaosan treatment effectively improved the colonic pathological and ultrastructural changes, upregulated the expression of ZO-1, occludin, and claudin-1 in the colon, and increased 5-HT levels in the hypothalamus and colonic mucosa.

Conclusions

Xiaoyaosan treatment attenuates depression-like behaviors caused by CUMS and ameliorates CUMS-induced abnormal intestinal permeability, which may be associated with the expression of TJs. These results suggest that Xiaoyaosan exerts an antidepressant effect that may be related to an improvement of intestinal barrier function via the brain-gut axis.

Xiao-Yao-San Formula Improves Cognitive Ability by Protecting the Hippocampal Neurons in Ovariectomized Rats

Xiao-Yao-San (XYS) decoction is a traditional Chinese medicine formula. This study aimed to investigate the effect of XYS on cognitive abilities and its underlying mechanism in ovariectomized rats. Female Sprague-Dawley rats were ovariectomized and treated with XYS (3 g/kg or 9 g/kg) by gavage, with subcutaneous injection of 17-β estradiol (E2, 2 μg/kg) as a positive drug control and gavage of 1 ml saline (0.9%) as a placebo control. After 6 weeks of treatment, rats were examined using the Morris water maze test. The estradiol level in the serum and hippocampus was measured by ELISA. Golgi staining was performed to observe neuronal morphology in the hippocampus. Apoptosis of hippocampal cells was observed by TUNEL staining. The protein content of N-methyl-D-aspartate receptor (NMDAR) 2A and 2B in the hippocampal CA1 region was determined by Western blot and immunohistochemistry. Expression of estrogen receptor (ER) and PI3K signaling was detected by Western blot. Compared with the sham group, both learning and memory were impaired in ovariectomized rats. Rats treated with E2 or high-dose XYS showed better learning and memory compared with the saline-treated rats. High-dose XYS significantly reduced escape latency in the spatial acquisition trial; meanwhile, the cross times and duration in the probe quadrant were increased in the spatial probe trial. High-dose XYS promoted the de novo synthesis of E2 content in the hippocampus but had no significant effect on the serum E2 level. Golgi staining indicated that high-dose XYS could increase the branch number and density of dendritic spines in the hippocampal CA1 area. TUNEL staining showed that high-dose XYS alleviated ovariectomy-induced neuronal apoptosis. The expression level of NMDAR2A and NMDAR2B in hippocampal CA1 was upregulated by XYS treatment. The beneficial effect of XYS was through activating ERα-PI3K signaling. In conclusion, high-dose XYS treatment can improve the cognitive abilities of ovariectomized rats by protecting the hippocampal neurons and restoring the hippocampal E2 level.

The role of allopregnanolone in depressive-like behaviors: Focus on neurotrophic proteins

Allopregnanolone (3α,5α-tetrahydroprogesterone; pharmaceutical formulation: brexanolone) is a neurosteroid that has recently been approved for the treatment of postpartum depression, promising to fill part of a long-lasting gap in the effectiveness of pharmacotherapies for depressive disorders. In this review, we explore the experimental research that characterized the antidepressant-like effects of allopregnanolone, with a particular focus on the neurotrophic adaptations induced by this neurosteroid in preclinical studies. We demonstrate that there is a consistent decrease in allopregnanolone levels in limbic brain areas in rodents submitted to stress-induced models of depression, such as social isolation and chronic unpredictable stress. Further, both the drug-induced upregulation of allopregnanolone or its direct administration reduce depressive-like behaviors in models such as the forced swim test. The main drugs of interest that upregulate allopregnanolone levels are selective serotonin reuptake inhibitors (SSRIs), which present the neurosteroidogenic property even in lower, non-SSRI doses. Finally, we explore how these antidepressant-like behaviors are related to neurogenesis, particularly in the hippocampus. The protagonist in this mechanism is likely the brain-derived neurotrophic factor (BFNF), which is decreased in animal models of depression and may be restored by the normalization of allopregnanolone levels. The role of an interaction between GABA and the neurotrophic mechanisms needs to be further investigated.

Sexually divergent changes in select brain proteins and neurosteroid levels after a history of ethanol drinking and intermittent PTSD-like stress exposure in adult C57BL/6J mice

Human studies reported that the number of past-year stressors was positively related to current drinking patterns, including binge drinking. In animal models, exposure to predator odor stress (PS), considered a model of traumatic stress, consistently increased ethanol intake. Recently, we reported that repeated PS significantly increased ethanol intake and had a synergistic interaction with prior binge drinking (binge group) in male but not in female C57BL/6J mice, when compared to mice without prior binge exposure (control group). The current studies utilized plasma and dissected prefrontal cortex (PFC) and hippocampal tissue from these animals and from age-matched naïve mice (naïve group). Western blots assessed relative protein levels of P450scc (an enzyme involved in the first step of steroidogenesis), of GABA_A receptor α2 and α4 subunits, and of two proteins involved in synaptic plasticity - ARC (activity-regulated cytoskeletal protein) and synaptophysin. Gas chromatography-mass spectrometry simultaneously quantified 10 neurosteroid levels in plasma. A history of ethanol drinking and PS exposure produced brain regional and sex differences in the changes in proteins examined as well as in the pattern of neurosteroid levels versus (vs.) values in naïve mice. For instance, P450scc levels were significantly increased only in binge and control female PFC and hippocampus vs. naïve mice. Some neurosteroid levels were significantly altered by binge treatment in both males and females, whereas others were only significantly altered in males. These sexually divergent changes in neurosteroid and protein levels add to evidence for sex differences in the neurochemical systems influenced by traumatic stress and a history of ethanol drinking.

Optimization of food deprivation and sucrose preference test in SD rat model undergoing chronic unpredictable mild stress

BACKGROUND

The chronic unpredictable mild stress (CUMS) model has long been considered the best model for exploring the pathophysiological mechanisms underlying depression. However, there are no widely recognised standards for strategies for modeling and for behavioral testing. The present study aimed to optimize the protocols for food deprivation and the sucrose preference test (SPT) for the CUMS model.

METHODS

We first evaluated the effects of different long periods of food deprivation on the body weight of Sprague Dawley (SD) rats by testing food deprivation for 24 hours (8:00-8:00+), food deprivation for 12 hours during the daytime (8:00-20:00) and food deprivation for 12 hours at night (20:00-8:00+). Next, we established a SD rat CUMS model with 15 different stimulations, and used body weight measurement, SPT, forced swim test (FST), open field test (OFT) and Morris water maze (MWM) test to verify the success of the modeling. In the SPT, consumption of sucrose and pure water within 1 and 12 hours was measured.

RESULTS

Twelve hours of food deprivation during the daytime (8:00-20:00) had no effect on body weight, while 12 hours of food deprivation at night (20:00-8:00+) and 24 hours of food deprivation (8:00-8:00+) significantly reduced the mean body weight of the SD rats. When SPT was used to verify the successful establishment of the CUMS rat model, sucrose consumption measured within 12 hours was less variable than that measured within 1 hour.

CONCLUSIONS

Twelve hours of food deprivation in the daytime (8:00-20:00) may be considered a mild stimulus for the establishment of a CUMS rat model. Measuring sucrose consumption over 12 hours is recommended for SPT.

Baicalin ameliorates chronic mild stress-induced depression-like behaviors in mice and attenuates inflammatory cytokines and oxidative stress

The natural flavonoid glycoside baicalin (BA) produces a variety of pharmaceutical effects, particularly for psychiatric/neurological disorders. This study evaluated the behavioral and neuroprotective effects of BA in mice subjected to chronic unpredictable mild stress, a model of depression. BA (25 and 50 mg/kg) significantly increased sucrose consumption and reduced immobility times in the tail suspension and forced swim tests, demonstrating that BA alleviated depression-like behaviors. Moreover, BA reduced the levels of inflammatory cytokines, such as interleukin 1β, interleukin 6, and tumor necrosis factor α, in serum and in the hippocampus. BA also abrogated increases in NMDAR/NR2B and Ca²⁺/calmodulin-dependent protein kinase II, and the decrease in phosphorylated ERK and reactive oxygen species production in mice subjected to chronic unpredictable mild stress. These findings suggested that the antidepressive effects of BA are due to the regulation of an NMDAR/NR2B-ERK1/2-related pathway and inhibition of inflammatory cytokines and oxidative stress. Thus, BA represents a potential candidate drug for patients suffering from depression.

Brain metabonomics study of the antidepressant-like effect of Xiaoyaosan on the CUMS-depression rats by 1H NMR analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyaosan (XYS), a famous TCM prescription with a long history of clinical use for relieving a wide variety of depression symptoms, consists of Radix Bupleuri (Bupleurum chinense DC.), Radix Angelicae Sinensis (Angelica sinensis (Oliv.) Diels), Radix PaeoniaeAlba (Paeonia lactiflora Pall.), Rhizoma Atractylodis Macrocepha lae (Atractylodes macrocephala Koidz.), Poria (Poria cocos (Schw.)Wolf), Radix Glycyrrhizae (Glycyrrhiza uralensis Fisch.), Herba Menthae Haplocalycis (Mentha haplocalyx Briq.), and Rhizoma Zin-giberis Recens (Zingiber officinale Rosc.).

AIM OF THE STUDY

We aimed to characterize the diversity and variation of two kinds metabolites of brain, i.e. aqueous and lipophilic metabolites, gaining comprehensive insights into the metabolic processes of depression-like behavior, and to reveal the mechanisms of antidepressant-like effects of XYS.

MATERIALS AND METHODS

We first established a CUMS (Chronic Unpredictable Mild Stress)-induced depression-like behavior model. We then extracted both aqueous and lipophilic metabolites of rat brains by a two-phase extraction method, which were subsequently characterized by two differential sequences of ¹H nuclear magnetic resonance (NMR). Multivariate analysis including Principal Components Analysis (PCA) and Orthogonal Partial Least Squares-Discriminate Analysis (OPLS-DA) was applied.

RESULTS

Metabolic profiling by PCA indicated that XYS significantly reversed the metabolic perturbation caused by CUMS. OPLS-DA showed a total of 15 metabolites including 6 lipophilic and 9 aqueous metabolites was screened as potential biomarkers involved in CUMS-induced depression-like behavior. On top of this, five pathways including (1)D-glutamine and D-glutamate metabolism, (2) valine, leucine and isoleucine biosynthesis, (3) alanine, aspartate and glutamate metabolism, (4) taurine and hypotaurine metabolism and (5) arginine and proline metabolism were recognized as the most influenced pathways associated with the process of CUMS-induced depression-like behavior. Notably, XYS significantly reversed abnormality of 5 aqueous and 4 lipophilic metabolites to normal, suggesting that XYS synergistically mediated abnormalities of multiple pathways (1), (3), (4) and (5).

CONCLUSIONS

It is the first report to investigate the antidepressant-like effects and underlying mechanisms of XYS from the perspective of brain metabolites. In a broad sense, this study brings novel and valuable insights to evaluate the efficacy of traditional Chinese medicine (TCM), to interpret mechanisms, and to provide the theoretical basis for further research on therapeutic mechanisms in clinical practice.

Xiaoyaosan Ameliorates Chronic Immobilization Stress-Induced Depression-Like Behaviors and Anorexia in Rats: The Role of the Nesfatin-1-Oxytocin-Proopiomelanocortin Neural Pathway in the Hypothalamus

Background: Chronic stress is an important risk factor for depression. The nesfatin-1 (NES1)-oxytocin (OT)-proopiomelanocortin (POMC) neural pathway, which is involved in the stress response, was recently shown to have an anorectic effect in the hypothalamus. Our previous study showed that Xiaoyaosan, a well-known antidepressant used in traditional Chinese medicine, effectively relieved appetite loss induced by chronic immobilization stress (CIS). However, whether Xiaoyaosan ameliorates depression-like behaviors and anorexia by regulating the NES1-OT-POMC neural pathway remains unclear. Objective: To investigate whether the antidepressant-like and anti-anorexia effects of Xiaoyaosan are related to the NES1-OT-POMC neural pathway in the hypothalamus. Methods: Rats were randomly divided into control, CIS, Xiaoyaosan treatment, and fluoxetine treatment groups. The rats in the CIS, Xiaoyaosan treatment, and fluoxetine treatment groups were subjected to CIS for 21 consecutive days, during which they were administered distilled water, a Xiaoyaosan decoction [3.854 g/(kg·d)] or fluoxetine [1.76 mg/(kg·d)], respectively, by gavage, and their body weights and food intake were monitored daily. The rats were subsequently subjected to the open field test and sucrose preference test. Then, the expression levels of corticosterone and NES1 in the serum and the expression levels of NES1, OT, POMC, and melanocortin-4 receptor (MC4R) in the hypothalamus were determined by real-time fluorescence quantitative polymerase chain reaction, Western blot analysis, and immunochemistry. Furthermore, immunofluorescence double staining was used to determine whether related proteins in the hypothalamic NES1-OT-POMC neural pathway were co-expressed. Results: Compared to control rats, rats exposed to CIS exhibited gradually less food intake and lower body weights and significantly increased concentrations of NES1 in the serum and paraventricular nucleus. Moreover, the expression levels of POMC, OT, and MC4R in the hypothalamus were significantly higher in the CIS group than those in the control group. However, these changes were reversed by pretreatment with Xiaoyaosan and fluoxetine. Specifically, the expression levels of members of the NES1-OT-POMC neural pathway were lower in the Xiaoyaosan-treated group than in the CIS group. Conclusion: Xiaoyaosan ameliorates CIS-induced depression-like behaviors and anorexia by regulating the NES1-OT-POMC neural pathway in the hypothalamus.

Influence of Xiaoyaosan on depressive-like behaviors in chronic stress-depressed rats through regulating tryptophan metabolism in hippocampus

BACKGROUND

Tryptophan metabolism has always been considered to play a vital role in mental disorder diseases, and how traditional Chinese formula Xiaoyaosan regulates the tryptophan metabolism is a complement to the pathogenesis of depression. This study established a depression rat model by the chronic immobilization stress (CIS) method and observed the change in tryptophan metabolism in hippocampus and the effects of Xiaoyaosan.

METHODS

Forty-eight male Sprague Dawley (SD) rats were randomly divided into the following four groups: control group, CIS group, Xiaoyaosan group, and fluoxetine group. The depression model was established by the 21-day CIS. The food intake and body weight were recorded, and the sucrose preference test (SPT), novelty suppressed feeding (NSF) test and open field test (OFT) were also used to evaluate the model. Then, the contents of tryptophan and 5-hydroxytryptamine (5-HT) in hippocampus were detected by the ELISA method, and the expression levels of tryptophan hydrogenase 2 (TPH2) and indoleamine 2,3-dioxygenase 1 (IDO1) in hippocampus were determined by quantitative reverse transcriptase polymerase chain reaction reaction (qRT-PCR) and Western blot methods.

RESULTS

The behavioral data showed a significant difference between the model group and the normal group. The 5-HT content in the hippocampi of CIS rats was significantly reduced, whereas the tryptophan content in the hippocampi of model rats was significantly increased. The TPH2 level in hippocampus of the model group was significantly decreased, and the IDO1 level was significantly increased. Xiaoyaosan and fluoxetine could significantly reverse these changes and had obvious curative effects.

CONCLUSION

The abnormal tryptophan metabolism existed in the hippocampi of chronic stress-depressed rats, which was closely related to the pathogenesis of depression. Xiaoyaosan could improve the tryptophan metabolism by regulating the expression levels of TPH2 and IDO1, thus exerting an antidepressant-like effect.