Modified Xiaoyaosan reverses aberrant brain regional homogeneity to exert antidepressive effects in mice

Effect of Xiaoyaosan on brain volume and microstructure diffusion changes to exert antidepressant-like effects in mice with chronic social defeat stress

Objective

Depression is a prevalent mental disorder characterized by persistent negative mood and loss of pleasure. Although there are various treatment modalities available for depression, the rates of response and remission remain low. Xiaoyaosan (XYS), a traditional Chinese herbal formula with a long history of use in treating depression, has shown promising effects. However, the underlying mechanism of its therapeutic action remains elusive. The aim of this study is to investigate the neuroimaging changes in the brain associated with the antidepressant-like effects of XYS.

Methods

Here, we combined voxel-based morphometry of T2-weighted images and voxel-based analysis on diffusion tensor images to evaluate alterations in brain morphometry and microstructure between chronic social defeat stress (CSDS) model mice and control mice. Additionally, we examined the effect of XYS treatment on structural disruptions in the brains of XYS-treated mice. Furthermore, we explored the therapeutic effect of 18β-glycyrrhetinic acid (18β-GA), which was identified as the primary compound present in the brain following administration of XYS. Significant differences in brain structure were utilized as classification features for distinguishing mice with depression model form the controls using a machine learning method.

Results

Significant changes in brain volume and diffusion metrics were observed in the CSDS model mice, primarily concentrated in the nucleus accumbens (ACB), primary somatosensory area (SSP), thalamus (TH), hypothalamus (HY), basomedical amygdala nucleus (BMA), caudoputamen (CP), and retrosplenial area (RSP). However, both XYS and 18β-GA treatment prevented disruptions in brain volume and diffusion metrics in certain regions, including bilateral HY, right SSP, right ACB, bilateral CP, and left TH. The classification models based on each type of neuroimaging feature achieved high accuracy levels (gray matter volume: 76.39%, AUC=0.83; white matter volume: 76.39%, AUC=0.92; fractional anisotropy: 82.64%, AUC=0.9; radial diffusivity: 76.39%, AUC=0.82). Among these machine learning analyses, the right ACB, right HY, and right CP were identified as the most important brain regions for classification purposes.

Conclusion

These findings suggested that XYS can prevent abnormal changes in brain volume and microstructure within TH, SSP, ACB, and CP to exert prophylactic antidepressant-like effects in CSDS model mice. The neuroimaging features within these regions demonstrate excellent performance for classifying CSDS model mice from controls while providing valuable insights into the antidepressant effects of XYS.

The effects and mechanisms of modified Xiaoyaosan on chronic unpredictable mild stress (CUMS)-induced depressive mice based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Clinical research and basic scientific experiments have shown that modified Xiaoyaosan (MXYS) has antidepressant effects, whose system mechanism however has not been thoroughly characterized.

AIM OF THE STUDY

This research was aimed at evaluating the treatment effects of MXYS on chronic unpredictable mild stress (CUMS)-induced depressive mice and exploring underlying mechanisms.

MATERIALS AND METHODS

Whether MXYS has effects on depression was investigated via the depressive behaviors of mice, electron microscopy, real-time quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, immunofluorescence (IF) staining and the stereotaxic injection of adeno-associated viruses (AAVs). In addition, network pharmacology was applied to predict relevant molecular targets and possible mechanisms and perform further in vivo validation.

RESULTS

MXYS is effective in ameliorating the depression-like symptoms of CUMS mice. It can stimulate autophagosome formation, activate the expression of microtubule-associated protein 1 light chain 3 (LC3B), autophagy-related gene 5 (Atg5), Atg7 and neuron-specific nuclear protein (NeuN), and decrease the protein expression sequestosome 1 (SQSTM1/p62). The autophagy-upregulating effect of MXYS was weakened by silencing. The network pharmacology analysis revealed that mitogen-activated protein kinase 1 (MAPK1), MAPK3, serine/threonine-protein kinase (AKT1), proto-oncogene tyrosine-protein kinase (SRC), PI 3 kinase p85 alpha (PIK3R1), catenin (cadherin-associated protein) beta 1 (CTNNB1) and human thrombin activator 1 (HRAS) may be of importance to treat depression by MXYS. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that metabolic and autophagy pathways, pathways in cancer and MAPK, phosphoinositide 3-kinase (PI3K)-Akt and rhoptry-associated protein 1 (Rap1) signaling pathways are involved in the antidepressant effects of MXYS. As suggested by Western blot, the anti-depression mechanism of MXYS is possibly associated with the extracellular signal-regulated protein kinase (ERK)/P38 MAPK signaling pathway.

CONCLUSION

The findings indicate the possible antidepressant effects of MXYS on CUMS mice via triggering autophagy to alleviate neuronal apoptosis and prompting autophagy, which may involve the ERK/P38 MAPK signaling pathway.

Xiaoyaosan Exerts Antidepressant Effect by Downregulating RAGE Expression in Cingulate Gyrus of Depressive-Like Mice

Xiaoyaosan (XYS), as a classic Chinese medicine compound, has been proven to have antidepressant effect in many studies, but its mechanism has not been clarified. In our previous studies, we found that chronic stress can induce depressive-like behavior and lead to emotion-related cingulate gyrus (Cg) dysfunction, as well as the decrease of neurotrophic factors and the increase of inflammatory-related proteins. Therefore, we speculated that XYS may play an antidepressant role by regulating the inflammation-related receptor of advanced glycation protein end product (RAGE) to affect the functional connectivity (FC) signal of the Cg and improve the depressive-like behavior. In order to verify this hypothesis, we analyzed the FC and RAGE expression in the Cg of depressive-like mice induced by chronic unpredictable mild stress (CUMS) and verified it with RAGE knockout mice. At the same time, we detected the effect of XYS on the depressive-like behavior, expression of RAGE, and the FC of the Cg of mice. The results showed that the FC of the Cg of depressive-like mice induced by CUMS was weakened, and the expression of RAGE was upregulated. The antidepressant effect of XYS is similar to that of fluoxetine hydrochloride, which can significantly reduce the depressive-like behavior of mice and inhibit the expression of the RAGE protein and mRNA in the Cg, and increase the FC of the Cg in mice. In conclusion, XYS may play an antidepressant role by downregulating the expression of RAGE in the Cg of depressive-like mice induced by CUMS, thereby affecting the functional signal and improving the depressive-like behavior.

Meranzin hydrate elicits antidepressant effects and restores reward circuitry

The burden of depression is enormous, and numerous studies have found that major depressive disorder (MDD) induces cardiovascular disorders (CVD) and functional dyspepsia (FD). Excitingly, meranzin hydrate (MH), an absorbed bioactive compound of Aurantii Fructus Immaturus, reverses psychosocial stress-induced mood disorders, gastrointestinal dysfunction and cardiac disease. Pharmacological methods have repeatedly failed in antidepressant development over the past few decades, but repairing aberrant neural circuits might be a reasonable strategy. This article aimed to explore antidepressant-like effects and potential mechanisms of MH in a rat model of unpredictable chronic mild stress (UCMS). Utilizing blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI), we sought to find reliable neurocircuits or a dominant brain region revealing the multiple effects of MH. The results show that compared with UCMS rats, MH (10 mg/kg/day for 1 week i.g.)-treated rats exhibited decreased depression-like behaviour; increased expression of brain-derived neurotrophic factor (BDNF) in the hippocampal dentate gyrus; and normalized levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT), and acylated ghrelin (AG). Additionally, the UCMS-induced rise in BOLD activation in the reward system was attenuated after MH treatment. A literature search shown that nucleus accumbens (NAc) and hypothalamus of the reward system might reveal multiple effects of MH on MDD-FD-CVD comorbidity. Further research will focus on the role of these two brain regions in treating depression associated with comorbidities.