Objective To investigate the effects of cadmium on proliferation, differentiation and mineralization in osteoblasts, and their evolution after cessation of exposure.
Methods The osteoblast cells were harvested by sequential enzyme digestion from calvaria of SD rats and then cultured. One group was treated with CdCl2 (0-2.000 μmol/L) continually for 72 h; another group was exposed to cadmium (0-2.000μmol/L)for 48h, then shifted to culture with a medium free of cadmium for 24h, then the proliferation was analyzed by methylthiazolyldiphenyl-tetrazolium bromide (MTT) method, and the alkaline phosphatase (ALP) activity was assayed by p-nitrophenyl phosphate (PNPP)method. The effects of cadmium chloride (0.500μmol/L)exposure lasting for 3-13d on osteoblast mineralization and evolution were also observed on 10d, 8d, 6d, and 0d after cessation of exposure.
Results Cadmium could inhibit the proliferation, ALP activity and mineralization of osteoblast cells. The proliferation, differentiation and mineralization ability of osteoblasts after cessation of cadmium exposure were still significantly lower than that of the control, P < 0.05. No obvious improvement in proliferation, differentiation and mineralization were observed in osteoblasts after the cessation of cadmium exposure compared to that in the continuous exposure group.
Conclusion Effects of cadmium on osteoblasts in the form of inhibition on proliferation, differentiation and mineralization remain even the exposure is blocked.
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