Modified Danzhi XiaoyaoSan inhibits neuroinflammation via regulating TRIM31/NLRP3 inflammasome in the treatment of CUMS depression.

ABSTRACT

The NLRP3 inflammasome is critically involved in the development of depression. The E3 ubiquitin ligase TRIM31 negatively regulates this process by promoting the degradation of NLRP3 through the ubiquitin-proteasome pathway. Modified Danzhi Xiaoyaosan (MDZXYS) has shown good therapeutic effect in both preclinical and clinical depression treatments, yet the underlying mechanisms of its antidepressant effects are not fully understood. In the present study, we aimed to explore the antidepressant mechanisms of MDZXYS, focusing on NLRP3 activation and ubiquitin-mediated degradation. We employed rats with depression induced by chronic unpredictable mild stress (CUMS) and conducted various behavioral tests, including the sucrose preference, forced swimming, and open field tests. Neuronal damage in CUMS-treated rats was assessed using Nissl staining. We measured proinflammatory cytokine levels using ELISA kits and analyzed NLRP3/TRIM31 protein expression via Western blotting and immunofluorescence staining. Our results disclosed that MDZXYS reversed CUMS-induced depression-like behaviors in rats, reduced proinflammatory cytokine levels (IL-1ß), and ameliorated neuronal damage in the prefrontal cortex. Additionally, CUMS activated the NLRP3 inflammasome in the prefrontal cortex and upregulated the protein expression of TRIM31. After MDZXYS administration, the expression of NLRP3 inflammasome-associated proteins was reduced, while the expression level of TRIM31 was further increased. Through co-localized immunofluorescence staining, we observed a significant elevation in the co-localization expression of NLRP3 and TRIM31 in the prefrontal cortex of the MDZXYS group. These findings suggest that inhibiting NLRP3 inflammasome-mediated neuroinflammation by modulating the TRIM31signaling pathway may underlie the antidepressant effects of MDZXYS, and further support targeting NLRP3 as a novel approach for the prevention and treatment of depression.