Protective effect of formononetin on hypoxic injuries of osteoblasts in vitro

Aim To investigate the effects of formononetin on survival rate,cellular cycle,apoptosis and differentiation of osteoblasts induced by hypoxia.Methods Rat osteoblasts were isolated from calvarias of newborn Sprague-Dawly by enzyme digestion,and hypoxic environment was made by triple-gases incubator.Rat osteoblasts was induced by hypoxia.After 36 hours,cell viability,LDH leakage rate,analysis of cellular cycle and apoptosis rate were compared among 10-6 mol·L-1 group,10-5 mol·L-1 group,10-4 mol·L-1 group,hypoxia control and normal control.Total RNA was isolated and the gene expression of HIF-1α,Bcl-2 and Caspase-3 was investigated by RT-PCR.48 hours after hypoxia,osteogenic differentiation markers including ALP activity and nodules were detected.Results Formononetin could significantly improve survival rate,ALP activity,area of calcified nodules and decrease LDH leakage rate,apoptosis,percentage of S+G2 phases.Besides,the mRNA level of HIF-1α and Bcl-2 was enhanced,and the mRNA level of Caspase-3 was inhibited.Conclusion Formononetin can protect osteoblasts from hypoxia and enhance the osteogenic differentiation of osteoblasts induced by hypoxia significantly.