expression of alkaline phosphatase during osteogenic differentiation of rat bone marrow stromal cells

introduction: bone marrow contains a population of stem cells capable of differentiating to osteoblast and forming the bone nodule by dexamethasone. material and methods: the stromal cells of bone marrow obtained from 4 to 6 weeks old spruge-dawely male rats were grown in primary culture for 7 days and subcultured for 18 days. the cells were cultured in either dmem medium containing 15% fetal calf serum and antibiotics as the controls or the above medium supplemented with osteogenic supplements (os): include 10 mm na-beta glycerophosphate (na-betagp), 10 nm dexamethasone (dex) and 50 g/ml ascordic acid (asa) as the examined cultures. after 6, 12 and 18 days of grow up in subculture, the cultures were examined for mineralization and alkaline phosphatase (apase) expression. results: mesenchymal stem cells (mscs) in examined cultures underwent a dramatic change in cellular morphology and a significat increase in apase activity by day 12. the deposition of a calcified matrix on the surface of the culture flasks became evident between days 12 and 18. conclusion: the addition of osteogenic supplements (os) to mscs cultures induced apase expression that contributes to cellular differentiation and mineralization of extracellular matrix.