[Insulin-like growth factor 1 promotes the proliferation and differentiation of human periodontal ligament stem cells into periodontal ligament fibroblasts].

Objective To investigate the effect of insulin-like growth factor 1 (IGF-1) on the proliferation and differentiation potential of human periodontal ligament stem cells (hPDLSCs). Methods The hPDLSCs were isolated by the limited dilution method. Surface markers of hPDLSCs were detected by flow cytometry. Cell clones were tested by crystal violet staining. The hPDLSCs were induced into osteoblasts and adipogenic by osteogenic and adipogenic medium. The influence of different concentrations of IGF-1 (1, 10, 30, 50, 100 ng/mL) on hPDLSCs was analyzed by CCK-8 assay. The expressions of collagen I α1 (Col1α1), collagen III α1 (Col3α1), runt-related transcription factor 2 (Runx2), bone sialoprotein (BSP), osteopontin (OPN), cementum protein 1 (CEMP1) and scleraxis (SCXA) were compared by means of real-time PCR. Col1, Col3, SCXA, Runx2 and CEMP1 protein expressions were determined by Western blotting. Results The hPDLSCs obtained by the limited dilution were positive for CD105 (95.4%), CD90 (96.1%) and negative for CD34 (1.58%), CD45 (1.74%). Single colonies were observed after cells were plated at low density by crystal violet staining. Alizarinred-positive mineral deposits and oil red O-positive cells indicated that the cultured cells had osteogenic and adipogenic potential. Proliferative potential of hPDLSCs was enhanced by IGF-1 in a dose-dependent manner. Real-time PCR showed that IGF-1 enhanced the expressions of Col1α1, Col3α1 and SCXA, while no significant change was found in the expressions of Runx2, BSP, OPN and CEMP1. Western blot analysis showed that the expressions of Col1, Col3 and SCXA increased significantly. Conclusion IGF-1 promotes proliferation and collagen synthesis of hPDLSCs, which further accelerates the differentiation into periodontal ligament fibroblast cells.