Study on osteogenic potential of cultured bone marrow stromal cells transfected with transforming growth factor β1 gene in vitro

Objective To study the osteogenic potential of cultured bone marrow stromal cells (BMSCs) transfected with transforming growth factor β1 (TGF β1) gene in vitro. Methods BMSCs were obtained from dual femoral greater trochanter in twenty New Zealand rabbits. Cultured cells were from the left trochanter (the experimental group) and from the right trochanter (the control group). BMSCs were transfected with the complexes of pcDNA3 TGF β1 and lipofectamine reagent in vitro. The cell proliferation was detected by MTT method and the morphological character of transfected BMSCs was observed. ALP staining and PNP method were used to measure ALP activity. In addition, the collagen Type Ⅰ propeptides and mineralized matrixes were examined by immunohistochemistry staining and tetracycline fluorescence labeling respectively. Results The morphological and biological characters of the transfected BMSCs were similar to those of osteoblasts and the cell proliferation was promoted. The cell layer displayed strong positive reaction by ALP staining and immunohistochemistry staining. The ALP activity was (3.51±0.12)U/ml in the pcDNA3 TGF β1 transfected group as compared with (1.72±0.08)U/ml in the void vector transfected group and (1.67±0.11)U/ml in the control group. PI value of collagen Type Ⅰ expression increased remarkably after transfection(0.167±0.001 in the transient expression group versus 0.043±0.001 in the control group). Mineralized matrixes formed earlier(on the 12th day) and were more in the experiment group than in the control group(on the 18th day). Conclusions Transfection with TGF β1 gene can promote the osteogenic potential of cultured BMSCs.