Zhizichi decoction alleviates depressive-like behaviors through modulating mitochondria-associated membrane via the...

Zhizichi Decoction (ZZCD), a traditional Chinese medicine (TCM), is derived from the combination of Gardenia jasminoides J. Ellis [Rubiaceae] and Semen Sojae Praeparatum, a fermented derivative of Glycine max (L.) Merr. [Leguminosae]. ZZCD has demonstrated anti-inflammatory properties and the potential to promote neural plasticity. Neuroinflammation is believed to contribute to the development of depressive symptoms.

This study investigates the potential antidepressant effects of ZZCD, focusing on its role in regulating neuroinflammatory responses and mitochondria-associated membrane (MAM) structure.

Using high-performance liquid chromatography (HPLC), we identified five active ingredients in ZZCD. We then evaluated its effect in a chronic social defeat stress (CSDS) mouse model. A combination of Network pharmacology analysis, Western-blot, immunostaining, enzyme-linked immunosorbent assay (ELISA), co-immunoprecipitation (CO-IP), mitochondrial transmembrane potential (ΔΨm), and transmission electron microscopy (TEM) was adopted to elucidate the mechanisms by which ZZCD improves MAM structure, inhibits neuroinflammation, and exerts antidepressant effects. Finally, according to the molecular docking results, a GRP75 overexpression viral vector was constructed to manipulate the MAM-related protein GRP75, further validating the mechanism of ZZCD's antidepressant effect.

ZZCD treatment significantly ameliorated depressive-like behaviors induced by CSDS in mice and reversed adverse changes in endoplasmic reticulum (ER) stress, MAM structure, and mitochondria injury. In addition, ZZCD effectively reduced microglial inflammatory activation and suppressed the increased expression of pro-inflammatory cytokines. Finally, the antidepressant effects of ZZCD were primarily mediated through the IP3R3-GRP75-VDAC1 complex, as demonstrated by the overexpression of the GRP75 protein.

In summary, ZZCD exerts antidepressant effects in the CSDS model by improving the MAM structure, alleviating neuroinflammation, and enhancing mitochondrial function.