Abstract
Mesenchymal stem cells (MSCs) contain multipotent cells and differentiate into osteoblasts, chondrocytes, and adiphocytes. Recently, MSCs have been used clinically in a tissue-engineering concept, but cell activity varies. It was found that the characteristics of extracellular matrices, type Tcollagen and/or fibronectin matrices, induced the osteoblastic differentiation of MSCs. Six weeks after cells were cultured with type I collagen and fibronectin, they formed mineralized tissue six times higher than other matrices. In this study, using “real time RT-PCR,” we assessed the expression of osteogenesis-related genes (alkaline phosphatase, BMP-2, osteocalcin, and cbfa-1) during osteoblastic differentiation by measuring their mRNA, quantitatively. The expression of the alkaline phosphatase gene increased time-dependently during osteoblastic differentiation until day 12, but expression induced by type I collagen and type I collagen and fibronectin decreased gradually. The expression of osteocalcin and the BMP-2 gene increased time-dependently; osteocalcin gene expression induced by type I collagen and fibronectin was about 6.2 times higher than non-induced cells. Expression of the cbfa-1 gene was different from that of type I collagen, fibronectin, and non-induced cells from day 12 and increased time-dependently. These findings were supported by alkaline phosphatase staining and immunofluoresence with an osteopontin antibody.
