Regulatory effects of simvastatin on osteoblast proliferation, differentiation and connexin 43 expression / 中国组织工程研究

ABSTRACT

BACKGROUND:The effects and molecular mechanism of simvastatin on the proliferation and differentiation of osteoblasts remain unclear. Especial y, we do not know much about the effects of connexin 43. OBJECTIVE:To evaluate the effects of simvastatin on the proliferation and differentiation of osteoblasts and the regulatory effect of simvastatin on the expression of osteogenic genes and connexin 43. METHODS:Newborn Sprague-Dawley rats were chosen and the cranium digestion method was used to culture osteoblasts. The different concentrations of simvastatin (0.062 5, 0.125, 0.25, 0.5 and 1.0μmol/L) were used to deal with osteoblasts. The proliferative effect of simvastatin on osteoblasts was measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The effect of simvastatin on osteoblast differentiation was measured with alkaline phosphatase activities. The mRNA and protein expression of osteogenic genes and connexin 43 were measured by real time quantitative RT-PCR and western blot assay. RESULTS AND CONCLUSION:There were no significant differences in absorbance values of simvastatin groups at 3 days (P>0.05). However, at 4 and 5 days, absorbance values were lower in the simvastatin groups than those in the control group (P<0.05). Compared with the control group, alkaline phosphatase activities of osteoblasts were greater in the simvastatin groups (P<0.05). Moreover, the effects of 0.25μmol/L simvastatin on alkaline phosphatase activities of osteoblasts were most significant. Osteocalcin, alkaline phosphatase activities, type I col agen and connexin 43 mRNA and protein expressions were increased after treatment with 0.25μmol/L simvastatin (P<0.05). These results indicated that simvastatin may inhibit the proliferation and improve the differentiation of osteoblasts by upregulating the mRNA and protein expression of osteogenic genes and connexin 43. These data may provide the new intervention target for osteoporosis treated with statins.