Saikosaponin D exerts antidepressant effect by regulating Homer1-mGluR5 and mTOR signaling in a rat model of chronic unpredictable mild stress

The protective effects of methylene blue on astrocytic swelling after cerebral ischemia-reperfusion injuries are mediated by Aquaporin-4 and metabotropic glutamate receptor 5 activation

Methylene blue (MB) was found to exert neuroprotective effect on different brain diseases, such as ischemic stroke. This study assessed the MB effects on ischemia induced brain edema and its role in the inhibition of aquaporin 4 (AQP4) and metabotropic glutamate receptor 5 (mGluR5) expression. Rats were exposed 1 h transient middle cerebral artery occlusion (tMCAO), and MB was injected intravenously following reperfusion (3 mg/kg). Magnetic resonance imaging (MRI) and 2,3,5-triphenyltetrazolium chloride (TTC) staining was performed 48 h after the onset of tMCAO to evaluate the brain infarction and edema. Brain tissues injuries as well as the glial fibrillary acidic protein (GFAP), AQP4 and mGluR5 expressions were detected. Oxygen and glucose deprivation/reoxygenation (OGD/R) was performed on primary astrocytes (ASTs) to induce cell swelling. MB was administered at the beginning of reoxygenation, and the perimeter of ASTs was measured by GFAP immunofluorescent staining. 3,5-dihydroxyphenylglycine (DHPG) and fenobam were given at 24 h before OGD to examine their effects on MB functions on AST swelling and AQP4 expression. MB remarkably decreased the volumes of T2WI and ADC lesions, as well as the cerebral swelling. Consistently, MB treatment significantly decreased GFAP, mGluR5 and AQP4 expression at 48 h after stroke. In the cultivated primary ASTs, OGD/R and DHPG significantly increased ASTs volume as well as AQP4 expression, which was reversed by MB and fenobam treatment. The obtained results highlight that MB decreases the post-ischemic brain swelling by regulating the activation of AQP4 and mGluR5, suggesting potential applications of MB on clinical ischemic stroke treatment.

Bupleurum in Treatment of Depression Disorder: A Comprehensive Review

The incidence of depression has been steadily rising in recent years, making it one of the most prevalent mental illnesses. As the pursuit of novel antidepressant drugs captivates the pharmaceutical field, the therapeutic efficacy of Traditional Chinese Medicine (TCM) has been widely explored. Chaihu (Bupleurum) has been traditionally used for liver conditions such as hepatitis, liver inflammation, liver fibrosis, and liver cancer. It is believed to have hepatoprotective effects, promoting liver cell regeneration and protecting against liver damage. In addition, Bupleurum has also been used as a Jie Yu (depression-relieving) medicine in China, Japan, Republic of Korea, and other Asian countries for centuries. This review article aims to summarize the research conducted on the antidepressant properties and mechanisms of Bupleurum, as well as discuss the potential of TCM formulas containing Bupleurum. This review highlights various antidepressant ingredients isolated from Bupleurum, including saikosaponin A, saikosaponin D, rutin, puerarin, and quercetin, each with distinct mechanisms of action. Additionally, Chinese herb prescriptions and extracts containing Bupleurum, such as Chaihu Shugansan, Xiaoyaosan, and Sinisan, are also included due to their demonstrated antidepressant effects. This review reveals that these Bupleurum compounds exhibit antidepressant effects through the regulation of neurotransmitter mechanisms (such as 5-HT and DA), the NMDA (N-methyl-D-aspartate) system, brain-derived neurotrophic factor (BDNF), and other intracellular signaling pathways. Collectively, this comprehensive review provides insights into the multiple applications of Bupleurum in the treatment of depression and highlights its potential as an alternative or complementary approach to traditional therapies. However, it is essential to consider the potential adverse effects and clinical restrictions of Bupleurum despite its promising potential. Further research is needed to elucidate its specific mechanisms of action and evaluate its effectiveness in human subjects.

Potential antidepressant effects of Traditional Chinese botanical drug formula Chaihu-Shugan-San and its active ingredients

Background: Depression is a severe mental disorder that poses a significant threat to both the physical and mental wellbeing of individuals. Currently, there are various methods for treating depression, including traditional Chinese herbal formulations like Chaihu-Shugan-San (CSS), which have shown effective antidepressant effects in both clinical and animal research. Objective: This review aims to provide a comprehensive synthesis of evidence related to CSS, considering both preclinical and clinical studies, to uncover its potential multi-level, multi-pathway, and multi-target mechanisms for treating depression and identify its active ingredients. Methods: A thorough search was conducted in electronic databases, including PubMed, MEDLINE, Web of Science, Google Scholar, CNKI, and Wanfang, using keywords such as "Chaihu Shugan" and "depression" to retrieve relevant literature on CSS and its active ingredients. The review process adhered to the PRISMA guidelines. Results: This review consolidates the mechanisms underlying antidepressant effects of CSS and its active ingredients. It emphasizes its involvement in the regulation of monoaminergic neurotransmitter systems, synaptic plasticity, and the hypothalamic-pituitary-adrenal axis, among other aspects. Conclusion: CSS exerts a pivotal role in treating depression through various pathways, including the monoaminergic neurotransmitter system, the hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, and the brain-gut axis. This review facilitates a comprehensive understanding of the current state of CSS research, fostering an in-depth exploration of the etiological mechanisms of depression and the potential discovery of novel antidepressant drugs.

Quercetin alleviates chronic unpredictable mild stress-induced depression-like behavior by inhibiting NMDAR1 with α2δ-1 in rats

BACKGROUND

Depression is a serious mental disorder and the most prevalent cause of disability and suicide worldwide. Chronic unpredictable mild stress (CUMS) can lead to a significant acceleration of depression development. Quercetin (Que) is a flavonoid compound with a wide range of pharmacological effects. Recent studies have shown that quercetin can improve CUMS-induced depression-like behavior, but the mechanism of its improvement is still unclear. α2δ-1 is a regulatory subunit of voltage-gated calcium channel, which can interact with N-methyl-D-aspartate receptor (NMDAR) to form a complex.

OBJECTIVE

In this study, we found that Que could inhibit the increase of α2δ-1 and NMDAR expression in rat hypothalamus induced by CUMS. In pain, chronic hypertension and other studies have shown that α2δ-1 interacts with the NMDAR to form a complex, which subsequently affects the expression level of NMDAR. Consequently, the present study aimed to investigate the antidepressant effect of Que in vivo and in vitro and to explore its mechanism of action in terms of the interaction between α2δ-1 and NMDAR.

METHODS

Rats were randomly exposed to two stressors every day for 4 weeks to establish a CUMS rat model, then sucrose preference test (SPT), forced swimming test (FST), tail suspension test (TST), and open field test (OFT) were performed to detect the behavior of CUMS rats, so as to evaluate whether the CUMS rat model was successfully established and the improvement effect of Que on CUMS-induced depression-like behavior in rats. Experimental techniques such as serum enzyme-linked immunosorbent assay (ELISA), immunofluorescence, Western blot, and co-immunoprecipitation, as well as in vitro experiments, were used to investigate the mechanisms by which Que exerts its antidepressant effects.

RESULTS

Behavioral and ELISA test results showed that Que could produce a reduction in the excitability of the hypothalamic-pituitary-adrenal (HPA) axis in CUMS rats and lead to significant improvements in their depressive behavior. Western blot, immunofluorescence, and co-immunoprecipitation experiments showed that Que produced a decrease in NMDAR1 and α2δ-1 expression levels and interfered with α2δ-1 and NMDAR1 binding. In addition, the neural regulation mechanism of Que on antidepressant effect in PC12 cells knocked out α2δ-1 gene was further verified. Cellular experiments demonstrated that Que led to a reversal of up-regulation of NMDAR1 and α2δ-1 expression levels in corticosterone-injured PC12 cells, while Que had no effects on NMDAR1 expression in PC12 cells with the α2δ-1 gene knockout.

CONCLUSIONS

Que has a good antidepressant effect and can significantly improve the depression-like behavior caused by CUMS. It exerts antidepressant effects by inhibiting the expression level of α2δ-1, interfering with the interaction between α2δ-1 and NMDAR, and then reducing the excitability of the HPA axis.

Targeting autophagy to counteract neuroinflammation: A novel antidepressant strategy

Depression is a common disease that affects physical and mental health and imposes a considerable burden on afflicted individuals and their families worldwide. Depression is associated with a high rate of disability and suicide. It causes a severe decline in productivity and quality of life. Unfortunately, the pathophysiological mechanisms underlying depression have not been fully elucidated, and the risk of its treatment is still presented. Studies have shown that the expression of autophagic markers in the brain and peripheral inflammatory mediators are dysregulated in depression. Autophagy-related genes regulate the level of autophagy and change the inflammatory response in depression. Depression is related to several aspects of immunity. The regulation of the immune system and inflammation by autophagy may lead to the development or deterioration of mental disorders. This review highlights the role of autophagy and neuroinflammation in the pathophysiology of depression, sumaries the autophagy-targeting small moleculars, and discusses a novel therapeutic strategy based on anti-inflammatory mechanisms that target autophagy to treat the disease.

The therapeutic effects of saikosaponins on depression through the modulation of neuroplasticity: From molecular mechanisms to potential clinical applications

Depression is a major global health issue that urgently requires innovative and precise treatment options. In this context, saikosaponin has emerged as a promising candidate, offering a variety of therapeutic benefits that may be effective in combating depression. This review delves into the multifaceted potential of saikosaponins in alleviating depressive symptoms. We summarized the effects of saikosaponins on structural and functional neuroplasticity, elaborated the regulatory mechanism of saikosaponins in modulating key factors that affect neuroplasticity, such as inflammation, the hypothalamic-pituitary-adrenal (HPA) axis, oxidative stress, and the brain-gut axis. Moreover, this paper highlights existing gaps in current researches and outlines directions for future studies. A detailed plan is provided for the future clinical application of saikosaponins, advocating for more targeted researches to speed up its transition from preclinical trials to clinical practice.

Saikosaponin-b2 Inhibits Primary Liver Cancer by Regulating the STK4/IRAK1/NF-κB Pathway

The development of primary liver cancer (PLC) is associated with chronic liver inflammation and the loss of associated tumor suppressor genes, which characterizes inflammation-related tumors. In this study, we aimed to explore the effect of saikosaponin-b2 (SS-b2) on the development of PLC and its effect of the STK4 expression and IRAK1/NF-κB signaling axis. In vitro and in vivo experiments showed that SS-b2 exerted potent anti-inflammatory and antitumor effects. A PLC model was induced in vivo by treating male BALB/c mice with diethylnitrosamine, while an inflammatory model was induced in vitro by exposing RAW 264.7 macrophages to lipopolysaccharides (LPS). After treating cancer mice with SS-b2, the serum levels of alpha-fetoprotein, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase significantly reduced. Ki67 expression also decreased. The carcinomatous lesions of the liver were attenuated. Similar results were observed in liver tissue and RAW 264.7 macrophages, where SS-b2 significantly elevated serine/threonine protein kinase 4 (STK4) expression and decreased the expression of interleukin-1 receptor-associated kinase 1 (IRAK1), nuclear factor-kappaB (NF-κB), and downstream inflammatory cytokines, thus exerting anti-cancer and anti-inflammatory effects. Moreover, we employed siRNA to silence the STK4 expression in HepG2 to investigate the anti-tumor effect of SS-b2 in vitro. The STK4 knockdown would upregulate IRAK1 and thus the activation of NF-κB activity revealed by the increase in the levels of proinflammatory cytokines, consequently impairing SS-b2-induced inhibition of liver cancer development. Consequently, SS-b2 effectively inhibited PLC by upregulating STK4 to suppress the IRAK1/NF-κB signaling axis and is a promising agent for treating this disease.

The antidepressant-like effects of Danzhi Xiaoyao San and its active ingredients

BACKGROUND

Depression is a severe mental illness that endangers human health. Depressed individuals are prone to sleep less and to the loss of appetite for food; their thinking and cognition processes, as well as mood, may even be affected. Danzhi Xiaoyao San (DXS), documented in the Internal Medicine Summary, has been used for hundreds of years in China and is widely applied traditionally to treat liver qi stagnation, liver and spleen blood deficiency, menstrual disorders, and spontaneous and night sweating. DXS can also clear heat and drain the liver. Presently, it is used frequently in the treatment of depression based on its ability to clear the liver and alleviate depression.

PURPOSE

To summarize clinical and preclinical studies on the antidepressant-like effects of DXS, understand the material basis and mechanisms of these effects, and offer new suggestions and methods for the clinical treatment of depression.

METHODS

"Danzhi Xiaoyao", "Danzhixiaoyao", "Xiaoyao", "depression" and active ingredients were entered as keywords in PubMed, Google Scholar, CNKI and WANFANG DATA databases in the search for material on DXS and its active ingredients. The PRISMA guidelines were followed in this review process.

RESULTS

Per clinical reports, DXS has a therapeutic effect on patients with depression but few side effects. DXS and its active ingredients allegedly produce their neuroprotective antidepressant-like effects by modulating monoamine neurotransmitter levels, inhibiting the hypothalamic-pituitary-adrenal (HPA) axis hyperfunction, reducing neuroinflammation and increasing neurotrophic factors.

CONCLUSION

Overall, DXS influences multiple potential mechanisms to exert its antidepressant-like effects thanks to its multicomponent character. Because depression is not caused by a single mechanism, probing the antidepressant-like effects of DXS could further help understand the pathogenesis of depression and discover new antidepressant drugs.

Pharmacological properties and derivatives of saikosaponins-a review of recent studies

OBJECTIVES

Saikosaponins (SSs) constitute a class of medicinal monomers characterised by a triterpene tricyclic structure. Despite their potential therapeutic effects for various pathological conditions, the underlying mechanisms of their actions have not been systematically analysed. Here, we mainly review the important anti-inflammatory, anticancer, and antiviral mechanisms underlying SS actions.

METHODS

Information from multiple scientific databases, such as PubMed, the Web of Science, and Google Scholar, was collected between 2018 and 2023. The search term used was saikosaponin.

KEY FINDINGS

Numerous studies have shown that Saikosaponin A exerts anti-inflammatory effects by modulating cytokine and reactive oxygen species (ROS) production and lipid metabolism. Moreover, saikosaponin D exerts antitumor effects by inhibiting cell proliferation and inducing apoptosis and autophagy, and the antiviral mechanisms of SSs, especially against SARS-CoV-2, have been partially revealed. Interestingly, an increasing body of experimental evidence suggests that SSs show the potential for use as anti-addiction, anxiolytic, and antidepressant treatments, and therefore, the related molecular mechanisms warrant further study.

CONCLUSIONS

An increasing amount of data have indicated diverse SS pharmacological properties, indicating crucial clues for future studies and the production of novel saikosaponin-based anti-inflammatory, efficacious anticancer, and anti-novel-coronavirus agents with improved efficacy and reduced toxicity.

(2R,6R)-hydroxynorketamine improves PTSD-associated behaviors and structural plasticity via modulating BDNF-mTOR signaling in the nucleus accumbens

BACKGROUND

Post-traumatic stress disorder (PTSD) is a mental illness caused by either experiencing or observing a traumatic event that is perceived to pose a serious risk to one's life. (2R,6R)-HNK has an alleviating effect on negative emotions, nevertheless, the mechanism of (2R,6R)-HNK action is unclear.

METHODS

In this study, the single prolonged stress and electric foot shock (SPS&S) method was used to establish a rat model of PTSD. After determining the validity of the model, (2R,6R)-HNK was administered to the NAc by microinjection using a concentration gradient of 10, 50, and 100 μM, and the effects of the drug in the SPS&S rat model were evaluated. Moreover, our study measured changes in related proteins in the NAc (BDNF, p-mTOR/mTOR, and PSD95) and synaptic ultrastructure.

RESULTS

In the SPS&S group, the protein expression of brain-derived neurotrophic factor (BDNF), mammalian target of rapamycin (mTOR), and PSD95 was reduced and synaptic morphology was damaged in the NAc. In contrast, after the administration of 50 μM (2R,6R)-HNK, SPS&S-treated rats improved their exploration and depression-linked behavior, while protein levels and synaptic ultrastructure were also restored in the NAc. With the administration of 100 μM (2R,6R)-HNK, locomotor behavior, and social interaction improved in the PTSD model.

LIMITATIONS

The mechanism of BDNF-mTOR signaling after (2R,6R)-HNK administration was not explored.

CONCLUSION

(2R,6R)-HNK may ameliorate negative mood and social avoidance symptoms in PTSD rats by regulating BDNF/mTOR-mediated synaptic structural plasticity in the NAc, providing new targets for the development of anti-PTSD drugs.

Research progress of traditional Chinese medicine compound "Xiaochaihu Decoction" in the treatment of depression

Depression is a common psychiatric disorder under the category of depression syndrome in Traditional Chinese Medicine (TCM) theory. Meanwhile, Xiaochaihu Decoction is a classical TCM formulation regulating Qi, resolving and dissipating stagnation. Clinically, the formulation has long been adopted to treat Shaoyang stagnation syndrome for depression syndrome. In this review, potential targets of action and the corresponding pathways of Xiaochaihu Decoction are explored for depression treatment via network pharmacology. The article also systematically summarizes the active components and pharmacological mechanisms of seven Chinese herbal medicine components in Xiaochaihu Decoction and guides the future study direction of Xiaochaihu Decoction, which may serve a promising treatment for depression.

18β-Glycyrrhetinic Acid Ameliorates Neuroinflammation Linked Depressive Behavior Instigated by Chronic Unpredictable Mild Stress via Triggering BDNF/TrkB Signaling Pathway in Rats

Evidence shows that inflammatory responses may encompass the onset of severe depressive illness. Traditionally used licorice contains 18β-glycyrrhetinic acid (18βGA), which has been demonstrated to reduce inflammation and oxidative stress. This study investigates the antidepressant effects of 18βGA and the underlying mechanism in rats exposed to chronic unpredictable mild stress (CUMS). Wistar rats were exposed to CUMS for 36 consecutive days to establish depression. 18βGA (10, 20, and 50 mg/kg) or fluoxetine was given once daily (from day 30 to day 36). Thereafter, behavior parameters (sucrose preference test, forced-swimming test, open-field test, body weight), pro-inflammatory cytokines, neurotransmitters, adrenocorticotropic hormone (ACTH), corticosterone (CORT), and liver biomarkers were studied. Immunohistochemistry and western blot analyses were conducted to investigate the protein's expression. 18βGA (20 and 50 mg/kg) treatment increased sucrose intake, locomotion in the open-field test, decreased immobility time in the forced swim test, and improved body weight in CUMS-exposed rats. The therapy of 18βGA dramatically declined cytokines, ACTH and CORT and improved 5HT and norepinephrine in CUMS rats. Furthermore, BDNF and TrkB proteins were down-regulated in CUMS group, which was increased to varying degrees by 18βGA at doses of 20 and 50 mg/kg. Therefore, 18βGA ameliorates depressive-like behavior persuaded by chronic unpredictable mild stress, decreases neuroinflammation, liver biomarkers, stress hormones, and improves body weight, brain neurotransmitter concentration via activating on BDNF/TrkB signaling pathway in both PFC and hippocampus in rats.

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.

Sinisan alleviates depression-like behaviors by regulating mitochondrial function and synaptic plasticity in maternal separation rats

BACKGROUND

Sinisan (SNS) consists of four kinds of herbs, which is the core of antidepressant prescription widely used in traditional Chinese medicine clinic treatment for depression induced by early life stress. However, the role and precise mechanism of SNS antidepressant have not yet been elucidated.

PURPOSE

This study aimed to investigate the mechanism SNS on antidepressant of regulating mitochondrial function to improve hippocampal synaptic plasticity.

METHODS

90 Sprague-Dawley (SD) rats male pups on Post-Natal Day (PND) 0 were randomly divided into Control group (ddH₂0), Model group (ddH₂0), Fluoxetine group (5.0 mg/kg fluoxetine), and SNS-L group (2.5 g/kg SNS), SNS-M group (5.0 g/kg SNS) and SNS-H group (10.0 g/kg SNS), 15 animals per group. Maternal separation (MS) from PND1 to PND21, drug intervention from PND60 to PND90, and behavior tests including sucrose preference test, open field test and forced swimming test from PND83 to PND90 were performed. Synaptic structure and mitochondrial structure were observed by TEM. The expression levels of PSD-95 and SYN were detected by immunohistochemistry and western blot test, the adenosine triphosphate (ATP) content in the hippocampus was detected by assay kits, and the expression levels of Mfn2, Drp1 and Fis1 protein were detected by western bolt test.

RESULTS

SNS can alleviate depression-like and anxiety-like behaviors in MS rats, improve the damage of synapses and mitochondria, reduce the decrease of ATP in hippocampus, and reverse the expression levels of PSD-95, SYN, Mfn2, Drp1, and Fis1 proteins.

CONCLUSION

SNS reduced the risk of early life stress induced depression disorder via regulating mitochondrial function and synaptic plasticity. Targeting mitochondrial may be a novel prospective therapeutic avenue for antidepressant.

Postsynaptic Proteins at Excitatory Synapses in the Brain—Relationship with Depressive Disorders

Depressive disorders (DDs) are an increasingly common health problem that affects all age groups. DDs pathogenesis is multifactorial. However, it was proven that stress is one of the most important environmental factors contributing to the development of these conditions. In recent years, there has been growing interest in the role of the glutamatergic system in the context of pharmacotherapy of DDs. Thus, it has become increasingly important to explore the functioning of excitatory synapses in pathogenesis and pharmacological treatment of psychiatric disorders (including DDs). This knowledge may lead to the description of new mechanisms of depression and indicate new potential targets for the pharmacotherapy of illness. An excitatory synapse is a highly complex and very dynamic structure, containing a vast number of proteins. This review aimed to discuss in detail the role of the key postsynaptic proteins (e.g., NMDAR, AMPAR, mGluR5, PSD-95, Homer, NOS etc.) in the excitatory synapse and to systematize the knowledge about changes that occur in the clinical course of depression and after antidepressant treatment. In addition, a discussion on the potential use of ligands and/or modulators of postsynaptic proteins at the excitatory synapse has been presented.