Effect of estrogen receptor beta on the osteoblastic differentiation function of human periodontal ligament cells

Objective: To investigate the effect of estrogen receptor beta (ER beta) on osteoblastic differentiation function of human periodontal ligament (hPDL) cells by measuring the alkaline phosphatase (ALP) activity and the production of osteocalcin (OCN) in vitro. Design: We employed a short interfering RNA (siRNA) technique to inhibit ER beta expression in hPDL cells; the cells were cultured with a saturating concentration of 17 beta-estradiol (10(-7) M). ALP activity was analysed by colorimetric assay using ALP kit and the amount of OCN was assessed by osteocalcin ELISA kit. Results: It was shown that estradiol significantly enhanced the ALP activity and the production of OCN in hPDL cells. However, the ALP activity and the production of OCN in hPDL-siER beta cells were not significantly changed after estradiol treatment. Conclusions: These results indicate that ER beta may play important roles in estrogen-induced effects on osteoblastic differentiation function of PDL cells and estrogen influences the bone formation capacity of PDL cells mainly via ER beta. (C) 2008 Elsevier Ltd. All rights reserved.