Effects of Xiaoyaosan on Stress-Induced Anxiety-Like Behavior in Rats: Involvement of CRF1 Receptor

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.

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

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

Clinical efficacy and safety of traditional Chinese medicine Xiao Yao San in insomnia combined with anxiety

BACKGROUND

Patients with long-term insomnia generally experience anxiety and depression. Traditional sleeping pills and anti-anxiety drugs have certain limitations. Xiao Yao San (XYS), a complementary and alternative therapy, has been widely used to treat insomnia combined with anxiety. This study aims to evaluate the efficacy and safety of XYS in the treatment of insomnia combined with anxiety.

METHODS

Related literature was retrieved from 8 electronic databases from the establishment time to March 2021. The subjects were diagnosed with insomnia combined with anxiety. We assessed the methodological quality of randomized controlled trials (RCTs) according to the Cochrane Handbook. Data analysis was conducted using RevMan 5.3 software.

RESULTS

The analysis includes 9 RCTs involving 681 patients. Meta-analysis supported that as an auxiliary drug for Western medicine (WM), XYS could enhance the clinical efficacy of insomnia calculated according to the traditional Chinese medicine (TCM) syndrome score scale (risk ratio [RR]: 1.26; 95% confidence interval [CI]: 1.13-1.43; P = .0002) and reduced the scores of Hamilton Anxiety Scale (mean difference [MD]: -5.19; 95% CI: -7.78 to -2.60; P < .001), Pittsburgh Sleep Quality Index (MD: -3.35; 95% CI: -4.86 to -1.84; P < .001), Self-rating Anxiety Scale (MD: -9.38; 95% CI: -10.20 to -8.75; P < .001), TCM syndrome score scale for insomnia (MD: -4.45; 95% CI: -6.65 to -2.24; P < .001), and TCM syndrome score scale for anxiety (MD: -5.54; 95% CI: -9.48 to -1.6; P = .006). The summary analysis also shows that the separate use of XYS was advantageous in reducing the scores of the Hamilton Anxiety Scale (MD: -3.70; 95% CI: -6.31 to -1.09; P = .005), Pittsburgh Sleep Quality Index (MD: -1.82; 95% CI: -2.39 to -1.24; P < .001), and Self-rating Anxiety Scale (MD: -10.79; 95% CI: -14.09 to -7.49; P < .001). The incidence of adverse events with XYS as an ancillary drug or used separately was lower than that in the WM.

CONCLUSION

Our systematic evaluation and meta-analysis showed that XYS combined with WM or XYS alone was beneficial for improving sleep quality and relieving anxiety. Due to the low methodological quality, small sample size, and significant heterogeneity of RCTs, more rigorous and scientific clinical trials are required to further evaluate the efficacy and safety of XYS.

PROSPERO REGISTRATION NUMBER

CRD42020190613.

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.

Behavioral and Oxidative Stress Changes in Mice Subjected to Combinations of Multiple Stressors Relevant to Irritable Bowel Syndrome

Background and Objectives: Irritable bowel syndrome (IBS) is a well-known functional gastrointestinal (GI) disorder exhibiting a wide range of symptoms due to individual variability and multifactorial etiology. Stress exposure is a major risk factor for the development of IBS. Here, we investigate the differential effects of psychological stress exposures on behavior and oxidative status in mice by using increasingly complex combinations of etiologic IBS-relevant stressors (maternal separation and chronic unpredictable mild stress combinations). Materials and Methods: Mice were subjected to three different combinations of psychological stress factors and subsequent behavioral cognitive and affective parameters and oxidative status markers (superoxide dismutase and glutathione peroxidase antioxidant activity and malondialdehyde level) in the brain and bowel tissues of the animals were analyzed. Results: GI transit modifications reflected by decreased fecal output, cognitive and affective behavioral deficits were observed in all stress exposed groups, but were more evident for the more complex combinations of stressors. Behavioral deficits were accompanied by mild oxidative stress occurring in the bowel and to a greater extent in brain tissue. Conclusions: The presented data depict the effect of various associations in mimicking IBS symptoms and comorbidities and suggest that an all-inclusive combination of early and adult-life psychological stressors is more effective in IBS symptoms modulation. Oxidative stress in both brain and bowel, suggestive for brain-gut molecular connectivity, may play an important role in IBS mechanistic.

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.

Translating traditional herbal formulas into modern drugs: a network-based analysis of Xiaoyao decoction

Background

Traditional Chinese medicine (TCM) encompasses numerous herbal formulas which play critical therapeutic roles through "multi-components, multi-targets and multi-pathways" mechanisms. Exploring the interaction among these mechanisms can certainly help to depict the core therapeutic function of herbal formulas. Xiaoyao decoction (XYD) is one of the most well-known traditional Chinese medicine formulas which has been widely applied to treat various diseases. In this study, taking XYD as an example, we proposed a network pharmacology-based method to identify the main therapeutic targets of this herbal concoctions.

Methods

Chemical data of XYD were retrieved from the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP), Traditional Chinese Medicines Integrated Database (TCMID) and Compound Reference Database (CRD) and screened oral bioavailability attributes from SwissADME using Veber's filter. Targets of sample chemicals were identified using the online tool similarity ensemble approach (SEA), and pathways were enriched using STRING database. On the basis of targets-pathways interactions from the enrichment, a "targets-pathways-targets" (TPT) network was constructed. In the TPT network, the importance of each target was calculated by the declining value of network efficiency, which represents the influential strength of a specific set-off target on the whole network. Network-based predictive results were statistically validated with existing experimental evidence.

Results

The TPT network was comprised of 279 nodes and 6549 edges. The declining value of network efficiency of the sample targets was significantly correlated with their involvement frequency in existing studies of XYD using Spearman's test (p < 0.001). The top 10% of candidate targets, such as AKT1, PIK3R1, NFKB1 and RELA, etc., were chosen as XYD's main therapeutic targets, which further show pharmacological functions synergistically through 11 main pathways. These pathways are responsible for endocrine, nutritional or metabolic diseases, neoplasms and diseases of the nervous system, etc.

Conclusions

The network pharmacology-based approach in the present study shows promising potential for identifying the main therapeutic targets from TCM formulas. This study provides valuable information for TCM researchers and clinicians for better understanding the main therapeutic targets and therapeutic roles of herbal decoctions in clinical settings.

An Integrated Pharmacology-Based Analysis for Antidepressant Mechanism of Chinese Herbal Formula Xiao-Yao-San

Clinical studies and basic science experiments have widely demonstrated the antidepressant and anxiolytic effects of the herbal formula Xiao-Yao-San (XYS). However, the system mechanism of these effects has not been fully characterized. The present study conducted a comprehensive network pharmacological analysis of XYS and sorted all pharmacologically active components (149) through the TCMSP webserver. Then, all potential molecular targets (449) were predicted, of which there were 99 genes clearly related to depression. To further investigate the mechanism of antidepressant effects of XYS, a compound-depression targets (C-DTs) network was constructed, and Gene Ontology (GO) functional and KEGG pathway enrichment analyses were performed for the 99 targets. Enrichment results revealed that XYS could regulate multiple aspects of depression through these targets, related to metabolism, neuroendocrine function, and neuroimmunity. Prediction and analysis of protein–protein interactions resulted in selection of three hub genes (AKT1, TP53, and VEGFA). In addition, a total of seven ingredients from XYS could act on these hub genes and they were identified through ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS), including paeoniflorin, quercetin, luteolin, acacetin, aloe-emodin, Glyasperin C, kaempferol. Hereafter, we investigated the effects of paeoniflorin and its predicted target, the results suggest that it can reverse the neurotoxicity produced by CORT and could be a neuroprotective effect by promoting the phosphorylation of Akt. Overall, our research revealed the complicated antidepressant mechanism of XYS, and also provided a rational strategy for revealing the complex composition and function of Chinese herbal formula.

Xiaoyaosan Produces Antidepressant Effects in Rats via the JNK Signaling Pathway

Background: Xiaoyaosan (XYS) has achieved definite curative effects in clinic. However, the mechanism is not clear. Previous studies of our team indicated XYS improved anxiety-like behaviors through inhibiting c-Jun N-terminal kinase (JNK) signaling pathway of hippocampus. Objectives: In the study, we explored whether the JNK signaling pathway is involved in the mechanism of XYS treating depression. Method: Forty-eight rats were divided randomly into 4 groups (n = 12): the control group (deionized water, p.o.), the model group (deionized water, p.o.), the fluoxetine group (2.08 mg/kg/day, p.o.), and the XYS group (3.9 g/kg/day, p.o.). All rats except for the control group were given continuous 21 days of chronic immobilization stress (CIS; 3 h/day). On day 29, the body weights and the behavioral tests, including the novelty suppressed feeding test, the open field test, and the elevated plus maze test, were measured. On day 30, all the rats were sacrificed, and three indices of the JNK signaling pathway were tested by Western blot. Results: The body weight and behavioral tests of all groups indicated that 21 days of CIS induced depression-like behaviors. After 21 days of treatment with fluoxetine and XYS, changes were seen in body weight, behaviors, and JNK, phosphorylated JNK (P-JNK), and phosphorylated c-Jun (P-c-Jun) levels in the hippocampus. Conclusions: XYS ameliorated the depression-like behaviors, potentially through affecting the JNK signaling pathway in the hippocampus.

Histamine H3 receptor antagonist E177 attenuates amnesia induced by dizocilpine without modulation of anxiety-like behaviors in rats

BACKGROUND

Alzheimer disease (AD) is the main cause of dementia in elderly people. The potential of histamine H3 receptor (H3R) antagonists as a pharmacological treatment of several neuropsychiatric diseases is well established.

METHODS

The novel non-imidazole-based H3R antagonist E177 was screened for its pro-cognitive effects on the inhibitory avoidance paradigm (IAP) and novel object recognition (NOR) task in a dizocilpine (DIZ)-induced model of amnesia in male Wistar rats. Donepezil, an acetylcholine esterase inhibitor, was used as the reference drug.

RESULTS

Acute systemic treatment with E177 (1.25, 2.5, 5, and 10 mg/kg intraperitoneally [i.p.]) significantly attenuated the cognitive impairments induced by DIZ in the IAP (all P-values <0.05, n=7), and the protective effect of the most promising dose of E177 (5 mg/kg) was abrogated when H3R agonist R-(α)-methylhistamine (RAMH; 10 mg/kg i.p.) was co-administered (P=0.281 for DIZ-amnesia group vs DIZ + E177 + RAMH group, n=7). The discrimination index calculated for E177 (5 mg/kg, i.p.) showed a significant memory-enhancing effect on DIZ-induced short-term memory impairment in the NOR task (P<0.05, n=6), with the enhancement nullified when animals were co-administered RAMH (10 mg/kg). Moreover, the results revealed that E177 (5 and 10 mg/kg, i.p.) did not alter the anxiety levels and locomotor activity of animals naïve to the open-field test (all P-values >0.05, n=8) or the elevated plus maze test (all P-values >0.05, n=6-8), which indicated that the E177-induced enhancement of memory performance in the IAP or NOR task was unrelated to changes in emotional response or in spontaneous locomotor activity.

CONCLUSION

The observed results suggested a possible contribution of H3Rs in the alteration of brain neurotransmitters that accompany neurodegenerative diseases, such as AD.

Modified Xiaoyaosan (MXYS) Exerts Anti-depressive Effects by Rectifying the Brain Blood Oxygen Level-Dependent fMRI Signals and Improving Hippocampal Neurogenesis in Mice

As the traditional Chinese herbal formula, Xiaoyaosan and its modified formula have been described in many previous studies with definite anti-depressive effects, but its underlying mechanism remains mystery. Previous work in our lab has demonstrated that depression induced by chronic stress could generate brain blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals disorder, accompanied by the impairment of hippocampal neuronal plasticity, decrease of brain-derived neurotrophic factor, and reduction of the number and complexity of adult neurons in the dentate gyrus. We hypothesized that herbal formula based on Xiaoyaosan could exert anti-depressive effects through restoring these neurobiological dysfunctions and rectifying BOLD-fMRI signals. To test this hypothesis, we examined the effect of modified Xiaoyaosan (MXYS) on depressive-like behaviors, as well as hippocampal neurogenesis and BOLD signals in a mice model of chronic unpredictable mild stress (CUMS)-induced depression. MXYS exerted anti-depressant effects on CUMS-induced depression that were similar to the effects of classical antidepressants drug (fluoxetine hydrochloride), with a significant alleviation of depressive-like behaviors, an improvement of hippocampal neurogenesis, and a reversal of activation of BOLD in the limbic system, particularly in the hippocampus. These results suggested that MXYS attenuated CUMS-induced depressive behaviors by rectifying the BOLD signals in the mice hippocampus. These novel results demonstrated that MXYS had anti-depressive effects accompanied by improving BOLD signals and hippocampal neurogenesis, which suggested that BOLD-fMRI signals in brain regions could be a key component for the evaluation of novel antidepressant drugs.

Xiaoyaosan Improves Depressive-Like Behaviors in Mice through Regulating Apelin-APJ System in Hypothalamus

Background: The apelin-APJ system has been considered to play a crucial role in HPA axis function, and how the traditional Chinese compound prescription Xiaoyaosan regulates the apelin-APJ system as a supplement to treat depressive disorders. Objective: To investigate the depression-like behaviors and expression of apelin and APJ in hypothalamus of chronic unpredictable mild stress (CUMS) mice and study whether these changes related to the regulation of Xiaoyaosan. Methods: 60 adult C57BL/6J mice were randomly divided into four groups, including control group, CUMS group, Xiaoyaosan treatment group and fluoxetine treatment group. Mice in the control group and CUMS group received 0.5 mL physiological saline once a day by intragastric administration. Mice in two treatment groups received Xiaoyaosan (0.25 g/kg/d) and fluoxetine (2.6 mg/kg/d), respectively. After 21 days of modeling with CUMS, the expression of apelin and APJ in hypothalamus were measured by real-time fluorescence quantitative PCR, western blot and immunohistochemical staining. The physical condition, body weight, food intake and behavior tests such as open field test, sucrose preference test and force swimming test were measured to evaluate depressive-like behaviors. Results: In this study, significant behavioral changes were found in CUMS-induced mice, meanwhile the expressions of apelin and APJ in the hypothalamus were changed after modeling. The body weight, food-intake and depressive-like behaviors in CUMS-induced mice could be improved by Xiaoyaosan treatment which is similar with the efficacy of fluoxetine, while the expressions of apelin and APJ in hypothalamus were modified by Xiaoyaosan. Conclusions: The data suggest that apelin-APJ system changes in the hypothalamus may be a target of depressive disorders, and the beneficial effects of Chinese compound prescription Xiaoyaosan on depressive-like behaviors may be mediated by the apelin-APJ system.

The Histamine H3 Receptor Antagonist DL77 Ameliorates MK801-Induced Memory Deficits in Rats

The role of Histamine H3 receptors (H3Rs) in memory, and the prospective of H3R antagonists in pharmacological control of neurodegenerative disorders, e.g., Alzheimer disease (AD) is well-accepted. For that reason, the procognitive effects of the H3R antagonist DL77 on cognitive impairments induced with MK801 were tested in an inhibitory passive avoidance paradigm (PAP) and novel object recognition (NOR) task in adult male rats, using donepezil (DOZ) as a standard drug. Acute systemic pretreatment with DL77 (2.5, 5, and 10 mg/kg, i.p.) significantly ameliorated memory deficits induced with MK801 in PAP (all P < 0.05, n = 7). The ameliorative effect of most promising dose of DL77 (5 mg/kg, i.p.) was reversed when rats were co-injected with the H3R agonist R-(α)-methylhistamine (RAMH, 10 mg/kg, i.p.) (p = 0.701 for MK801-amnesic group vs. MK801+DL77+RAMH group, n = 6). In the NOR paradigm, DL77 (5 mg/kg, i.p.) counteracted long-term memory (LTM) deficits induced with MK801 (P < 0.05, n = 6-8), and the DL77-provided effect was similar to that of DOZ (p = 0.788, n = 6-8), and was reversed when rats were co-injected with RAMH (10 mg/kg, i.p.) (p = 0.877, n = 6, as compared to the (MK801)-amnesic group). However, DL77 (5 mg/kg, i.p.) did not alter short-term memory (STM) impairment in NOR test (p = 0.772, n = 6-8, as compared to (MK801)-amnesic group). Moreover, DL77 (5 mg/kg) failed to modify anxiety and locomotor behaviors of animals innate to elevated-plus maze (EPM) (p = 0.67 for percentage of time spent exploring the open arms, p = 0.52 for number of entries into the open arms, p = 0.76 for percentage of entries into the open arms, and p = 0.73 number of closed arm entries as compared to saline-treated groups, all n = 6), demonstrating that the procognitive effects observed in PAP or NOR tests were unconnected to alterations in emotions or in natural locomotion of tested animals. These results signify the potential involvement of H3Rs in modulating neurotransmitters related to neurodegenerative disorders, e.g., AD.

The Histamine H3 Receptor Antagonist E159 Reverses Memory Deficits Induced by Dizocilpine in Passive Avoidance and Novel Object Recognition Paradigm in Rats

The involvement of histamine H3 receptors (H3Rs) in memory is well known, and the potential of H3R antagonists in therapeutic management of neuropsychiatric diseases, e.g., Alzheimer disease (AD) is well established. Therefore, the effects of histamine H3 receptor (H3R) antagonist E159 (2.5–10 mg/kg, i.p.) in adult male rats on dizocilpine (DIZ)-induced memory deficits were studied in passive avoidance paradigm (PAP) and in novel object recognition (NOR) using pitolisant (PIT) and donepezil (DOZ) as standard drugs. Upon acute systemic pretreatment of E159 at three different doses, namely 2.5, 5, and 10 mg/kg, i.p., 2.5 and 5 but not 10 mg/kg of E159 counteracted the DIZ (0.1 mg)-induced memory deficits, and this E159 (2.5 mg)-elicited memory-improving effects in DIZ-induced amnesic model were moderately abrogated after acute systemic administration of scopolamine (SCO), H2R antagonist zolantidine (ZOL), but not with H1R antagonist pyrilamine to the animals. Moreover, the observed memory-enhancing effects of E159 (2.5 mg/kg, i.p.) were strongly abrogated when animals were administered with a combination of SCO and ZOL. Furthermore, the E159 (2.5 mg)-provided significant memory-improving effect of in DIZ-induced short-term memory (STM) impairment in NOR was comparable to the DOZ-provided memory-enhancing effect, and was abolished when animals were injected with the CNS-penetrant histamine H3R agonist R-(α)-methylhistamine (RAMH). However, E159 at a dose of 2.5 mg/kg failed to exhibit procognitive effect on DIZ-induced long-term memory (LTM) in NOR. Furthermore, the results observed revealed that E159 (2.5 mg/kg) did not alter anxiety levels and locomotor activity of animals naive to elevated-plus maze (EPM), demonstrating that improved performances with E159 (2.5 mg/kg) in PAP or NOR are unrelated to changes in emotional responding or in spontaneous locomotor activity. These results provide evidence for the potential of drugs targeting H3Rs for the treatment of neuropsychiatric disorders, e.g., AD.

Xiao-Yao-San, a Chinese Medicine Formula, Ameliorates Chronic Unpredictable Mild Stress Induced Polycystic Ovary in Rat

Chronic stress induces endocrine disturbance, which contributes to the development of polycystic ovary syndrome (PCOS), a condition that remains a challenge for clinicians to cope with. The present study investigated the effect of Xiao-Yao-San (XYS), a traditional Chinese medicine formula used for treatment of gynecological disease, on the chronic stress-induced polycystic ovary and its underlying mechanism. Female Sprague-Dwaley rats underwent a 3 weeks chronic unpredictable mild stress (CUMS) procedure to establish the PCOS model, followed by 4 weeks treatment with XYS (0.505 g/kg or 1.01 g/kg) by gavage. Granulosa cells were exposed to noradrenaline (1 mM) in vitro for 24 h, followed by incubation with or without XYS-treated rat serum for 24 h. Post-treatment with XYS ameliorated CUMS-induced irregular estrous cycles and follicles development abnormalities, decrease of estradiol and progesterone level as well as increase of luteinizing hormone in serum, reduced cystic follicles formation and the apoptosis and autophagy of granulosa cells, attenuated the increase in dopamine beta hydroxylase and c-fos level in locus coeruleus, the noradrenaline level in serum and ovarian tissue, and the expression of beta 2 adrenergic receptor in ovarian tissue. Besides, XYS alleviated the reduction of phosphorylation of ribosomal protein S6 kinase polypeptide I and protein kinase B, as well as the increase of microtubule-associated protein light chain 3-I to microtubule-associated protein light chain 3-II conversion both in vivo and in vitro. This study demonstrated XYS as a potential strategy for CUMS induced polycystic ovary, and suggested that the beneficial role of XYS was correlated with the regulation of the sympathetic nerve activity.

Xiaoyaosan exerts anxiolytic-like effects by down-regulating the TNF-α/JAK2-STAT3 pathway in the rat hippocampus

Although the anxiolytic-like effects of Xiaoyaosan, a Chinese herbal formula, have been described in many previous studies, its underlying mechanism remains undefined. The cytokine tumour necrosis factor-α (TNF-α) and its closely associated janus kinase 2 (JAK2)-signal transducer and activator of transcription (STAT3) signalling pathway regulate the neuro-inflammatory response in the brain, thus participating in the development of anxiety. Our purpose was to investigate whether the anxiolytic-like effects of Xiaoyaosan are related to the TNF-α/JAK2-STAT3 pathway in the hippocampus. We examined the effects of Xiaoyaosan on behaviours exhibited in the elevated plus maze test, open field test and novelty-suppressed feeding test as well as hippocampal neuron damage and changes in the TNF-α/JAK2-STAT3 pathway in a rat model of chronic immobilization stress (CIS)-induced anxiety. Xiaoyaosan exerts anxiolytic-like effects on CIS-induced anxiety, with a significant alleviation of anxiety-like behaviours, an attenuation of hippocampal neuron damage, and a reversal of the activation of the TNF-α/JAK2-STAT3 pathway in the hippocampus that are similar to the effects of the JAK2 antagonist AG490. However, Xiaoyaosan and AG490 failed to effectively regulate apoptosis-related factors, including Bax and Caspase-3. These results suggest that Xiaoyaosan attenuates stress-induced anxiety behaviours by down-regulating the TNF-α/JAK2-STAT3 pathway in the rat hippocampus.

Xiao Yao San Improves the Anxiety-Like Behaviors of Rats Induced by Chronic Immobilization Stress: The Involvement of the JNK Signaling Pathway in the Hippocampus

The current study evaluated the effects of Xiao Yao San (XYS) on anxiety-like behaviors and sought to determine whether the c-Jun N-terminal kinase (JNK) signaling pathway is involved. A total of 40 rats were divided into 5 groups (n=8): the control group (deionized water, per os (p.o.)), the model group (deionized water, p.o.), the SP600125 group (surgery), the per se group (surgery), and the XYS group (3.9 g/kg/d, p.o.). A 1% dimethyl sulfoxide (DMSO) citrate buffer solution (2 µL/ventricle/d) and SP600125 (10 µg/ventricle, 2 µL/ventricle/d) were separately and bilaterally injected into the rats of the two surgery groups via the ventricular system of the brain. All but the control group underwent 14 d of chronic immobilization stress (CIS; 3 h/d). On day 15, the body weights of all of the rats were measured; additionally, the rats were subjected to the elevated plus maze (EPM) and novelty suppressed feeding (NSF) tests. Finally, JNK signaling pathway indices, including phosphorylated JNK (P-JNK), JNK, phosphorylated c-Jun (P-c-Jun) and cytochrome C (Cyt-C), were examined. After modeling, the body weight and behavioral analyses of the model rats indicated that this modeling method induced anxiety-like behaviors. P-JNK, JNK, and P-c-Jun were altered in the hippocampus of the model rats. After 14 d of treatment with XYS and SP600125, rat body weight and behaviors as well as P-JNK, JNK, and P-c-Jun had changed. However, no significant difference in Cyt-C was found. XYS improves the anxiety-like behaviors induced by CIS, which might be related to the JNK signaling pathway in the hippocampus.