BACKGROUND:The enamel matrix derivative has been used in the clinical treatment of severe periodontitis; however, the mechanism(s) by which enamel matrix derivative promotes periodontal regeneration is stil obscure. OBJECTIVE:To explore the effects of enamel matrix derivatives on the differentiation and proliferation of periodontal ligament stem cels. METHODS:Periodontal ligament stem cels were isolated and identified from human teeth. Cloning forming efficiency, surface antigen expression and pluripotency were detected and identified. Enamel matrix derivatives with different concentrations (20, 50, 100 mg/L) were used to culture periodontal ligament stem cels for 2 and 4 weeks. Colagen synthesis and mineralized nodule formation were detected using Trichrom staining and Von Kosa’s staining, respectively; real-time RT-PCR was employed to detect expressions of colagen type I, osteocalcin, and RUX2; MTT and cel growth rate assay were used to detect the proliferation of periodontal ligament stem cels. RESULTS AND CONCLUSION:Periodontal ligament stem cels were spindle-shaped and showed a higher colony forming efficiency than periodontal ligament cels. The expressions of surface antigens of periodontal ligament stem cels-CD105, CD29, CD45, CD44 were respectively 99.8%, 99.7%, 1.26%, 98.8%, indicating periodontal ligament stem cels have the multilineage differentiation potential. Enamel matrix derivatives improve the colagen synthesis and mineralization nodule formation of periodontal ligament stem cels in a time-dose dependent manner. They also can improve the expression of osteogensis-related genes colagen type I, osteocalcin, RUX2 and proliferation of periodontal ligament stem cels.