Directed differentiation of rat bone marrow stromal cells into osteoblast in vitro

The marrow stromal cells (MSCs) of Wistar rats were isolated from other marrow cells and expanded by applying its strong adherent ability to plastic dish. The morphology, differentiation and secretion of calcified matrix of MSCs were studied by cover slip culture, common histological staining, histochemical staining and the determination of alkaline phosphatase (ALP) activity and calcium content. It was shown that the cultured rat MSCs were spindle-shaped. Adipocytes and myocytes could be found in cultured cells. Under osteogenic induction condition, MSCs changed greatly in appearance, accompanied by the increase of ALP activity and calcium content. After 16 days, mineralized nodular aggregates were observed that indicated the formation of osteoblasts and osteocytes. It can be concluded that the rat MSCs have the capacity to differentiate into osteoblast, adipocyte and myocyte, however, among them, the potentiality of differentiation into osteoblast is the strongest and can be used as seed cells in bone tissue engineering.