MRC1 and major depressive disorder: On the one hand, it regulates the neurosteroid receptor PGMRC1 pathway in microglia, promotes the transformation of microglia into repair type, and increases tissue repair factors (such as CD206, TGM2, VEGFA, TIMP1, FGF1, PTN) expression, promote repair; on the other hand, regulate ERα, ERβ pathway, inhibit microglia to pro-inflammatory transformation, reduce pro-inflammatory factors In conclusion, microglia play a complex and diverse role in maintaining CNS homeostasis and participating in MDD, which deserves further exploration and study.