Effects of placentin on osteoblast proliferation and differentiation in vitro

Objective To investigate the effects of placentin extracted from lamb placenta on rat calvarium osteoblast proliferation and differentiation in vitro. Methods Different dilutions of placentin were added to the cultured osteoblasts from calvarium of newborn SD rats. The final concentrations of placentin were 0.625% , 1.25% , 2.5% , 5% ,and 10% . The MTT method was employed to detect the osteoblast proliferation after culture with placentin for 24 h, 48 h, and 96 h separately. The osteoblast differentiation was evaluated by detecting activities of alkaline phosphatase (ALP) using PNPP method after culture with placentin for 5 days. Mineralized nodules were stained with alizarin after culture with placentin for 31 days, and the areas of nodules were measured and computed by digitized image analyses. Results The OD values by MTT method in all placentin groups were much higher than that in control vehicle group(P 0.01) and were in dose-dependent manner; placentin in concentrations of 2.5 % and 5 % showed better effects. ALP activities in all placentin groups were significantly higher than that in control group (P 0.01) . The summed areas of mineralized nodules in 2.5% placentin group were significantly higher than that in control group (P 0.01). Conclusions Placentin extracted from lamb placenta stimulates the proliferation, differentiation and mineralization of cultured osteoblasts from SD rat calvarium in vitro.