Recent studies have found that retinoic acid can induce the osteogenic differentiation of embryonic stem cells and multiple adult stem cells.OBJECTIVE:
To observe the effect of retinoic acid on osteogenic differentiation of porcine periodontal ligament stem cells (PDLSCs).METHODS:
Porcine PDLCs were harvested by using outgrowth method; PDLSCs were isolated by limited dilution of culture cells for single cell clone. Immunofluorescence was used to detect the expression of STRO-1 and immunocytochemistry to detect the expression of vimentin and pan-Cytokeratin (PCK) of porcine PDLSCs. Cell counting kit8 (CCK8) was applied to evaluated cell proliferation of PDLSCs. The colony formation of porcine PDLSCs ratio was assayed. Third passage PDLSCs were induced with mineralized conditional medium containing retinoic acid, ascorbic acid and β-glycerophosphate. Mineralized nodules were studied by Alizarin red S staining. Osteopontin, osteocalcin, collagen type I and collagen type III were detected by immunocytochemistry.RESULTS AND CONCLUSION:
Porcine PDLSCs expressed STRO-1 and vimentin, and the result of pan-Cytokeratin was negative. Porcine PDLSCs colony formation ratio was 2.8%. PDLSCs induced by retinoic acid showed positive expression of alkaline phosphatase at 14 days and positive expression of Alizarin red S at 21 days. Osteopontin, osteocalcin, collagen type I were positive but collagen type III was negative at 21 days. These findings indicate that retinoic acid can be an effective inducer of osteogenic differentiation of porcine PDLSCs.