Gan-Mai-Da-Zao decoction ameliorates depressive-like behaviors in CUMS mice via the microbiota-metabolism-inflammation axis.

BACKGROUNDGan-Mai-Da-Zao decoction (GMDZ), a traditional Chinese formulation used as both food and medicines, exhibits antidepressant effects. However, its underlying mechanisms, particularly those involving the gut-brain axis, remain unclear.

PURPOSETo integrate gut microbiota profiling, metabolomics, and neuroinflammation to systematically elucidate GMDZ's antidepressant mechanisms.

STUDY DESIGN AND METHODSMice with depression-like behaviors were induced using a chronic unpredictable mild stress (CUMS) approach. Behavioral tests, multi-omics approaches (metabolomics, 16 s rRNA sequencing), and molecular biology techniques (histopathology, immunofluorescence, ELISA, qPCR, Western blot) were employed to investigate GMDZ's multi-target mechanisms.

RESULTSWe identified 108 bioactive components, with 58 detected in plasma and 43 in the cerebral cortex, confirming systemic exposure and cerebral penetration of key constituents. GMDZ significantly ameliorated depressive-like behaviors and attenuated associated neuronal and colonic pathological damage. Mechanistically, GMDZ exerted its antidepressant effects through three novel and interconnected pathways: (1) Modulating gut microbiota composition and altering fecal and plasma metabolite profiles; (2) Reducing peripheral and central pro-inflammatory cytokines levels and suppressing NLRP3 inflammasome pathway activation; and (3) Enhancing blood-brain barrier (BBB) integrity by up-regulating occludin and claudin-5.

CONCLUSIONGMDZ exerts antidepressant effects via a novel multi-target regulatory mechanism involving the microbiota-metabolite-inflammation axis. This study significantly advances our understanding of GMDZ's gut-brain axis mechanism and offers a new paradigm for mechanistic investigations of traditional Chinese medicine.