Abstract: Objective To investigate the effects of nicotine stimulation on proliferation and differentiation of human dental pulp stem cells. Methods Human dental pulp stem cells were culture and cell surface antigen was identified by flow cytometry. The cultured dental pulp stem cells were stimulated by nicotine (10^－4, 10^－3 and 10^－2 mol/L) at different concentrations, after 0, 1, 2, 3 and 4 d of culture, the proliferation of cells were detected by CCK8 assay; alizarin red staining to detect the formation of mineralized nodules during cell differentiation, RT-qPCR and Western blot were used to detect the expression of dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), osteopontin (OPN) and the expression of MAPK pathway-related proteins such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 (p-ERK, p-JNK, p-p38). Results On the 3rd and 4th day of culture, the A value of nicotine stimulation was significantly lower than that of control group (P＜0.05); compared with the control group, the number of mineralized nodules, the expression of DSPP, ALP, OPN mRNA and protein, the expression of p-ERK, p-JNK and p-p38 protein were significantly decreased when nicotine was stimulated (P＜0.05). Conclusions Nicotine inhibits the proliferation and osteogenic differentiation of human dental pulp stem cells.

Key words: nicotine, dental pulp stem cells, proliferation, differentiation