Modulation of Th17/Treg Balance by Total Flavonoids from Semen Cuscutae through PGRMC2 in a Diminished Ovarian Reserve Rat Model

Diminished ovarian reserve (DOR) is a critical challenge in reproductive health, leading to reduced fertility and hormonal imbalances. Current treatments such as assisted reproductive technologies and hormone replacement therapy often have limited success and adverse effects. Progesterone receptor membrane component 2 (PGRMC2) is a protein essential for various reproductive processes and is involved in ovarian folliculogenesis, with its increased expression associated with DOR. This study investigates the protective mechanisms of total flavonoids from Semen Cuscutae (TFSC) on ovarian reserve through PGRMC2 modulation and T helper 17 cell (Th17)/regulatory T cell (Treg) immune balance in a DOR rat model. DOR was induced in rats by administering 50 mg/kg tripterygium glycosides (TG) via intragastric administration once daily for 15 days. Various analytical techniques were used to assess the effects of TFSC, including immunohistochemistry for ovarian tissue analysis, Western blotting to measure PGRMC2 protein expression, flow cytometry for evaluating Th17/Treg ratio, and Enzyme-linked immunosorbent assay (ELISA) to quantify serum cytokine levels. Results demonstrate that TFSC enhances ovarian function, up-regulates PGRMC2 expression, and restores immune homeostasis, highlighting its potential as an alternative therapeutic strategy. By elucidating TFSC's role in immune modulation and ovarian function, this study paves the way for developing targeted therapies to improve outcomes for women with DOR.