Steroidogenic effect of Erxian decoction for relieving menopause via the p-Akt/PKB pathway in vitro and in vivo

Abstract

Erxian decoction (EXD), an empirical Chinese medicine formula, is clinically used for menopause in China. Previous data from our group revealed that EXD possesses steroidogenic effect on natural menopausal Sprague-Dawley-rats (SD-rats). However, the mechanistic studies on steroidogenic effects of EXD are still inadequate. Hence, the mechanisms of steroidogenic effects of EXD were studied in vitro and in vivo in this study. Menopause causes a decline of endocrine function and a series of symptoms. In this study, 16-20-month-old female SD rats with a low serum estradiol level were employed. Their endocrine functions after treatment with EXD (4.1g/kg) were assessed by determination of their serum estradiol level. Proteins involved in the steroidogenic pathway including StAR, 17βHSD, 3βHSD, aromatase, and activation of phosphorylated Protein Kinase B (p-Akt/PKB), as well as estradiol receptor proteins (ERα & ERβ) after EXD treatment were analyzed. Kinase inhibition assay was conducted to confirm the mechanism of steroidogenic effects of EXD in vitro. MCF-7 and BT-483 breast cancer cells were used to investigate whether EXD stimulated breast cancer cell proliferation. Results revealed a significantly ameliorated serum estradiol level, and a significantly increased expression of ovarian aromatase and PKB in the EXD-treated rats. EXD attenuated 17β-estradiol stimulated proliferation of breast cancer cells. The results obtained from immunoblotting and measurements of serum estradiol level of the present investigation revealed that EXD may relieve the menopausal syndrome through an upregulation of ovarian aromatase and p-PKB expression without stimulating the growth of breast cancer cells.