Effect of calcium sulfate on gene expression in differentiation of human BMSCs into osteoblasts

Objective To investigate the effect of calcium sulfate (CS) on the osteogenic gene expression in the differentiation process from human bone marrow stromal cells (BMSCs) to osteoblasts, and explore its possible biological mechanism in repairing bone defects. Methods CS-dissolved (test group) and conventional (control group) osteoblast-induced fluids were added into human BMSCs culture flasks (3 in each team) respectively for induction and differentiation to osteoblasts, and the cells were observed under a microscope until the 7th day. RNA was extracted from the cultured cells, and purification and quality tests were performed. After cDNA was synthesized, osteogenesis polymerase chain reaction (PCR) microarrays were used to examine the differently expressed osteogenic genes between two groups. Results We found that cells in both groups grew well and proliferated gradually. However, the osteogenic differentiation potential in test group was significantly better than in control group. The microarrays detected 89 kinds of genes, including 23 which changed significantly in expression ( Fold change ＞ 2,P ＜ 0. 05 ). The genes up-regulated more than 2 times included AMELY, BMP2, COL4A3, COMP, EGF, FLT1, IGF1,ITGA2, MMP10, MMP2, TGFB2, TGFBR1, VDR and VEGFA, while the genes down-regulated more than 2 times included COL2A1, COL15A1, COL1A1, COL1A2, COL5A1, CSF2, FGF1, ITGA3 and MMP8. Conclusion CS promoted the transforming process from human BMSCs to osteoblasts, which may be related to the up-regulation of osteoblastic gene expression and the increased synthesis of active factors.This suggested that CS has potential osteoinductive activity and can improve the bone repairing capacity of cells when used as a kind of ideal substitute bone repairing material. Key words: Bone marrow stromal cells; Calcium sulfate; Gene microarray; Osteogenisis