Protective effect of genistein on hypoxic injuries of osteoblasts cultivated in vitro

OBJECTIVE: To investigate the effect of genistein on osteoblast proliferation, cellular cycle, apoptosis and differentiation of osteoblasts cultivated under hypoxia conditions. METHOD: Rat osteoblasts were isolated from calvarias by enzyme digestion and a hypoxic model was established by in a triple-gas incubator. Rat osteoblasts were grouped into the normoxic control group, the hypoxia control group and the hypoxia administration group which was subdivided into Ge-6 group, Ge-5 group and Ge-4 group, to which genistein was administered at doses of 1 x 10(-6), 1 x 10(-5), 1 x 10(-4) mol x L(-1). The cell survival rate, lactic dehydrogenase leakage rate, apoptosis and differentiation of osteoblasts were observed for each group at 3 h after hypoxia, and the gene expression of HIF-1alpha, Bcl-2, Caspase-3 was detected by Real time RT-PCR. Forty-eight hours after hypoxia, osteogenic differentiation markers including alkaline phosphatase activity and nodules were detected. RESULT: Compared with the hypoxia control group, the hypoxia administration group displays a significant increase in the survival rate and a decreased in LDH leakage rate, apoptosis rate and percentage of S + G2 phases. Besides, the mRNA level of HIF-1alpha and Bcl-2 were enhanced, the mRNA level of Caspase-3 was inhibited. CONCLUSION: Genistein has an effect on protecting osteoblasts from hypoxia.