Cornus Officinalis Total Glycosides Alleviate Granulomatous Lobular Mastitis via the B7‐CD28/CTLA‐4 Costimulatory Pathway

Cornus officinalis total glycosides (COTG) derived from the traditional Chinese medicine Cornus officinalis, is a natural immunosuppressant and has been extensively studied in immunomodulation and immunosuppression. This study aimed to explore the effects of COTG on granulomatous lobular mastitis (GLM) and its associated mechanisms. Compared to the model group, COTG effectively ameliorated histopathological damage to breast tissue, reduced mammary gland suppuration, and enhanced the blood‐milk barrier. Additionally, COTG treatment reduced the total number of T cells and B cells in GLM rats, significantly improving clinical indicators such as P‐selectin, E‐selectin, and intercellular cell adhesion molecule‐1. We also observed downregulation of CD28 and B7 expression levels, an upregulation of cytotoxic T lymphocyte‐associated antigen‐4 (CTLA‐4) expression, and a significant decrease in inflammatory marker levels in the COTG group. COTG exerts an anti‐inflammatory effect in GLM by stimulating CTLA‐4, inhibiting the B7‐CD28 signaling pathway affecting T cell activation, and promoting the blood‐milk barrier. These findings suggest that COTG could be a promising therapeutic option for managing GLM, potentially improving patient outcomes by modulating immune responses and reinforcing the blood‐milk barrier.