Objective To evaluate the effect of nicotine on cell proliferation. Methods The cells were cultured with DMEM medium containing 10% fetal bovine serum with 0, 1×10-4 mol·L-1, and 1×10-3 mol·L-1 nicotine for up to 3, 5, 7, 10, 14 days. The cell proliferation was evaluated by MTT. The alkaline phosphatase（ALP） activity was estimated by PNPP. The expression of collagen typeⅠ（COL1） and osteocalcin（OCN） were estimated by reverse transcriptionpolymerase chain reaction（RT-PCR）. Results Nicotine suppressed the cell proliferation. ALP activity increased to peak on 10 days in control and 1×10-4 mol·L-1 nicotine. COL1 expression increased to peak on 10 days in control and 1×10 -4 mol·L -1 nicotine, but there was decreased to the minimum on 10 days and increased on 14 days in 1×10-3 mol·L-1 nicotine. OCN expression increased to peak on 10 days in control, and increased in 1×10-4 mol·L-1 nicontine from 3 days to 14 days, but there wasn′t significant change in 1×10-3 mol·L-1 nicontine. Conclusion Nicotine suppresses osteogenesis through a decrease in ALP and COL1 production by osteoblasts.
