Effect of smoking on the proliferation capacity and osteogenic potential of human dental pulp stem cells (DPSCs)

BACKGROUND Recently, mesenchymal stem cells (MSCs) have proven to have a high potentiality in tissue regeneration. However, genetic diseases or certain environmental risk factors, such as smoking, may compromise the functioning of MSCs, thus leading to a change in the expected clinical outcomes. OBJECTIVES The aim of this study was to investigate the proliferation capacity and osteogenic potential of dental pulp stem cells (DPSCs) in smokers in comparison with non-smokers. MATERIAL AND METHODS Mesenchymal stem cells were isolated from the cultured dental pulp tissue from the third molars of 5 smokers and 5 non-smokers. The proliferation capacity of DPSCs derived from both groups was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) proliferation assay. Alizarin red staining and the gene expression analysis of the alkaline phosphatase (ALP) and osteocalcin (OC) genes were performed in order to assess osteogenic differentiation. RESULTS The MTT proliferation assay revealed that the mean absorbance rate of the DPSCs of the nonsmokers was significantly higher than that of the group of smokers (p < 0.0001). When stained with alizarin red after 21 days of osteogenic induction, fewer calcium deposits were observed among the smokers. Moreover, the ALP and OC gene expression was significantly higher in the differentiated DPSCs of the nonsmokers (p < 0.05). CONCLUSIONS The group of smokers showed a reduced cell viability. The expression of the ALP and OC genes was lower in the DPSCs of the smokers. Therefore, smoking has a negative impact on the proliferation and regenerative potential of human MSCs.