The effect of Smad6 RNA interference on BMP-2 induced osteogenic differentiation of mesenchymal stem cells

Objective To investigate the effect of Smad6 mRNA interference on bone morphogenetic protein 2(BMP-2) induced osteogenic differentiation of bone marrow mesenchymal stem cells(MSCs).Methods The bone marrow MSCs of mice were cultured and underwent BMP-2 induced osteogenic differentiation.The cells were divided into 3 groups: the cells in group A were transfected with recombinant Smad6 RNA interference vector,which was labeled with green fluorescent protein(GFP),and the cells in group B were transfected with control vector,and the cells in group C served as controls.The activity of alkaline phosphonate(ALP) and levels of osteocalcin were detected at five days after transfection by ALP staining and radioimmunoassay,respectively.The formation of mineralization nodus was also examined by alizarin red staining.Results The GFP was obviously expressed in MSCs after viral transfection,and viral transfection efficiency reached 98.5%.As compared with group B,Smad6 RNA interference increased significantly ALP activity and osteocalcin levels in group A(P0.01),however,both ALP activity and osteocalcin levels in group C were significantly lower than those in the other two groups(P0.01).The results of alizarin red staining showed that the counts of mineralization nodus in group A were significantly more than those in group B(P0.05),but no mineralization nodus was found in group C.Conclusion Smad6 mRNA interference can promote effectively BMP-2 induced osteogenic differentiation of MSCs,which may be a valuable method for bone regeneration for bone defect in bone tissue engineering.