Electroconvulsive therapy modulates brain plasticity in male depression: Links to gut microbial metabolites and diet-derived regulation of Wnt/BDNF signaling.

Electroconvulsive therapy (ECT) stands as the most effective intervention for treatment-resistant depression; however, its interaction with dietary regulation of the gut-brain axis has not been thoroughly explored. This study aimed to elucidate the mechanistic link between ECT, gut microbiota remodeling, short-chain fatty acid (SCFA) production, and neural plasticity. In this study, mice were subjected to chronic restraint stress (6 h/d for 28 consecutive days) to establish a depression-like model. Utilizing a translational approach that incorporated behavioral assessments, multimodal neuroimaging techniques such as PET-CT and laser speckle contrast imaging, along with multiomics analyses including metagenomics, metabolomics, and transcriptomics in rodent models, we demonstrated that ECT induced significant gut microbiota remodeling, characterized by an enrichment of SCFA-producing genera like Lactobacillus and Bifidobacterium. This remodeling was associated with restored intestinal barrier integrity and elevated plasma SCFA levels. Mechanistically, these microbial metabolites activated hippocampal Wnt/β-catenin signaling pathways, enhancing synaptic plasticity restoration, while concurrent probiotic supplementation further amplified brain-derived neurotrophic factor (BDNF) expression via SCFA-dependent epigenetic mechanisms. Neuroimaging corroborated the normalization of cerebral glucose metabolism and hemodynamic function post-ECT. In conclusion, our findings unveil a novel gut-brain communication pathway by which ECT exerts its antidepressant effects, positioning SCFAs as vital mediators connecting microbial metabolic alterations to neural plasticity. This research not only redefines the role of nutritional biochemistry in neuromodulation but also suggests the potential of microbial metabolite monitoring to tailor antidepressant therapies for enhanced efficacy.