Estrogenic Effect of the Extract of QingYan Formula on Reproductive Tissues in Immature Mice

A Chinese herbal preparation, QingYan formula (QYF), has been used clinically for kidney-invigorating. However, no evidence base links QYF to estrogen replacement therapy. In this study, the estrogenic effects of QingYan formula 70% ethanol extract (QYFE) were investigated in immature mice. Immature mice were treated with QYFE at doses of 1, 2, and 4g/kg for 7 days. QYFE treatments promoted vaginal cornification and prolonged the estrus status of the immature mice, promoted the growth and development of uterus and vagina, upregulated ERα and ERβ expression at protein level in uterus and vagina, increased the level of estradiol (E₂), and decreased concentration of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in serum. This study demonstrated that QYFE exerts estrogenic effects by stimulating biosynthesis of estrogen and increasing estrogen receptors (ERs) in target tissues and provided an evidence base for QYFE treatment instead of estrogen replacement therapy.