OBJECTIVETo investigate the effects of Osthol on the proliferation and differentiation of osteoblasts of rats (rat calvarial osteoblasts, ROB) cultured in vitro.

METHODSThe neonatal SD rat skull was segregated, and enzyme digestion was used to obtain bone cells which were cultured in MEM containing 10% FBS. The medium was changed every three days, and serial subcultivation was performed when cells covered with 90% of the culture dish. The Osthol was added to 96-well plates with final concentration of 1 x 10(-4) mol/L, 1 x 10(-5) mol/L, 1 x l0(-6) mol/L and 1 x10(-7) mol/L, and MTT method was used to evaluate the proliferation. Differentiation analysis: the alkaline phosphatase (ALP) activity was determined at the 3rd, 6th, 9th, 12th and 15th days separately after osteogenic induction culture. The synthesis of type I collagen was observed using immunohistochemical method at the 8th day. The ALP stain was performed at the 12th day. The alizarin red staining was done and calcified nodules was counted at the 14th day.

RESULTSThe Osthol with final concentration of 1 x 10(-4) mo/L inhibit the proliferation of ROB. The Osthol with final concentration of 1 x 10(-5) mol/L had no obvious influence on the proliferation of ROB, but it significantly promoted the activity of ALP, enhanced the synthesis of collagen type I and increased the number of calcified nodules.

CONCLUSIONThe Osthol with final concentration of 1 x 10(-5) mol/L can promote differentiation and maturation of ROB, which may be active ingredients of Chinese drugs for the osteoporosis prophylaxis.