Effect of nicotine on morphology, proliferation, and osteogenic differentiation of human periodontal ligament stem cells and its mechanism

Abstract

Objective To investigate the effect of nicotine on the morphology, proliferation, and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs), and to analyze the influence mechanism. Methods The subjects were 120 orthodontic dental patients who were treated at our department of stomatology from March, 2015 to March, 2017. They all had healthy premolars. They were randomly divided into group A, group B, group C, and a control group, 30 cases for each group. PDLSCs was cultured in vitro, and different concentrations of nicotine medium were used to stimulate PDLSCs. The concentration of nicotine in group A was 10-4 mol/L, group B 10-3 mol/L, and C group 10-2 mol/L; and the control group was added with no- nicotine culture. The WST-1 kit was used to detect the proliferation of PDLSCs and to analyze the expression of PDLSCs related osteogenic differentiation gene after nicotine stimulation. Results The morphological changes of PDLSCs in group A were significant; and the cell count was lower in group A than in group B, group C, and the control group. The PDLSCs morphologies of group B and group C were similar, and the cells in the control group grew well. The 24, 48, 72, and 96 h proliferation levels were lower in group A, group B, and group C than in the control group, and were lower in group A and group B than in group C, with statistical differences (all P<0.05).The cell proliferation abilities at 96 h in group A, group B, and group C were lower than those at 24, 48, and 72 h, with statistical differences (all P<0.05). The inhibition rate of PDLSCs was higher in group A and group B than in group C, and in group A than in group B, with statistical differences (all P<0.05). The inhibition rates of PDLSCs in group A, group B, and group C at 96 h were significantly higher than those at 24, 48, and 72 h, with statistical differences (all P<0.05). The expression level of PDLSCs osteogenic differentiation genes was lower in group A, group B, and group C than in the control group at all the time points, lower in group A than in group B and group C, and lower in group B than in group C, with statistical differences (all P<0.05). Conclusion Nicotine can cause changes in PDLSCs and decrease the cells’ proliferation and osteogenic differentiation ability. The greater the concentration, the longer the action time is, the more likely it is related to their toxic effects and their effects on the expressions of mitochondria and TLR4. Key words: Proliferative ability; Periodontal ligament stem cells; Nicotine; Osteogenesis differentiation