Abstract: Objective To investigate the effect of p38 signal pathway on the osteogenic differentiation of periodontal ligament cells in vitro.Methods Human periodontal ligament cells (PDLCs) was obtained from the third molar and cultured in vitro.Cells from the third passage were cultured in the osteogenic medium， and 10 nM SB203580(an inhibitor of the p38 signaling pathway) was added in the medium in experimental group for 4 weeks.Then the qPCR and Alizarin red S staining were applied to evaluate the osteogenic capability of PDLCs.Results Osteogenic induction could promote the phosphorylation of p38,and inhibition of the phosphorylation of p38 could down-regulate the expression of Runx2,ALP,OPN and OCN,and decrease the formation of calcium nodule,in PDLCs.Conclusions The p38 signal pathway plays a crucial role on the osteogenic differentiation of PDLCs in vitro.

Key words: p38, periodontal ligament cells, osteogenic differentiation