Zinc ion concentration affects proliferation and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells / 中国组织工程研究

ABSTRACT

BACKGROUND: Zinc ion is a necessary metal trace element in human body, which plays an important role in inhibiting osteoclast activity and promoting osteogenic differentiation. However, the effect of zinc ion at different concentrations on osteogenic differentiation of rabbit bone marrow mesenchymal stem cells has been rarely studied. OBJECTIVE: To evaluate the effects of zinc ion at different concentrations on the proliferation and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells for exploring the appropriate zinc ion concentration. METHODS: Bone marrow mesenchymal stem cells were extracted from the long bone marrow of rabbits and passaged. The cells were divided into six groups, including 10-4, 10-5, 10-6, 10-7 and 10-8 mol/L zinc ion groups, and blank control group. The cell proliferation activity was measured by Cell Counting Kit-8 and the growth curve was drawn. Alkaline Phosphatase Assay kit was used to evaluate the osteogenic differentiation ability of the cells, and the growth activity of the cells was shown by Live-Dead Cell Staining Kit. The mineralization ability of the cells was observed by alizarin red S staining. The expression of osteogenic genes was detected by fluorescence quantitative polymerase chain reaction. RESULTS AND CONCLUSION: The number of cells in each group showed an increasing trend with the prolongation of time except for the 10-4 mol/L zinc ion group. After 5 days of culture, the number of cells was highest in the 10-7 mol/L zinc ion group, but lowest in the 10-4 mol/L zinc ion group. Alkaline phosphatase activity was highest when zinc ion concentration was 10-7 mol/L, but lowest at the 10-4 mol/L zinc ion after cell culture for 14 days. The method of Live-Dead Cell Staining revealed the number of viable cells was highest in the 10-7 mol/L zinc ion group. All cells were almost dead in the 10-4 mol/L zinc ion group. Calcium nodule formation was visible, and the expression level of osteogenic genes was highest in the 10-7 mol/L zinc ion group after 14 days of cell culture. These findings suggest that zinc ion can effectively promote the proliferation and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells in a certain concentration range. The promoting effects of zinc ion on proliferation, osteogenic induction and mineralization are strongest. Therefore, the addition of a suitable concentration of zinc ions in the medium is beneficial for the osteogenic differentiation of rabbit bone marrow mesenchymal stem cells.