[The effect of estrogen on proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells].

PURPOSE: Different concentrations of 17 β-estradiol (E2) were applied in the osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs), and the proliferation and apoptosis of BMSCs were explored. METHODS: BMSCs were obtained from the femurs and tibias of SD rats. The proliferation curve was conducted to rBMSCs in culture medium containing 0, 10(-9), and 10(-7) mol/L 17 β-estradiol by CCK-8 for 7 days. Annexin V and PI for flow cytometry were applied to detect the impact of E2 on apoptosis of rBMSCs. After 1, 7, 11 and 14 days of osteogenic induction, the activity of alkaline phosphatase (ALP) was assayed; ALP staining was performed on day 7 and day 14; Alizarin red staining for calcium deposits was carried out on day 21. Concentrations of 0, 10(-9), and 10(-7) mol/L 17 β-estradiol were administrated to rBMSCs for real-time PCR of osteogenic related genes on day 1, 3, 5, 7, 14, and day 21. The data was statistically analyzed using SPSS 19.0 software package. RESULTS: The effect of 17 β-estradiol on proliferation and apoptosis of rBMSCs was not obvious. However, after osteogenic induction, the ALP activity and Alizarin red staining were significantly stronger in the groups containing 17 β-estradiol. Especially, the use of 17 β-estradiol with the concentration of 10(-9) mol/L enhanced the expression of osteogenic related genes like RUNX2, ALP, COL I, and OCN, which was significantly higher than other groups. CONCLUSIONS: 17 β-estradiol promotes osteogenic differentiation of BMSCs in a dose-dependent pattern in vitro.