Tanshinone IIA attenuates estradiol-induced polycystic ovarian syndrome in mice by ameliorating FSHR expression in the ovary

Tanshinone IIA (TSIIA) is a major component of Salvia miltiorrhiza, a Chinese herb that exhibits a therapeutic effect on polycystic ovary syndrome (PCOS). The present study replicated PCOS via the neonatal treatment of estradiol in mice. Estrous cycles, body and ovarian weight, serum levels of testosterone and estradiol were determined. Histological examination of ovaries was performed. The mRNA and protein levels of aromatase luteinizing hormone receptor and follicle-stimulating hormone (FSHR) in ovaries and granule cells were assayed by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. TSIIA was revealed to reverse all disorders induced by estradiol treatment, including prolonged estrous cycles, increased body and ovarian weight, increased atretic cyst-like follicles and decreased corpus luteum, large antral follicles and preovulatory follicles. These improvements in PCOS as a result of TSIIA treatment are likely due to the revised testosterone/estradiol balance, as TSIIA reversed the decrease in aromatase mRNA, the enzyme that converts androgen to estrogen. As the expression of aromatase is regulated by the FSH pathway, TSIIA-mediated elevation in FSHR expression may lead to the upregulation of aromatase. Therefore, TSIIA revises the balance of androgen and estrogen by rescuing the reduced expression of FSHR and aromatase, thus attenuating murine PCOS. The current study aimed to further the application of natural drugs in the treatment of PCOS to confront the side effects of hormone drugs and expand the use of TSIIA.