Effects of bone morphogenetic protein 2 and basic fibroblast growth factor 2 on proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cell sheet / 中国组织工程研究

ABSTRACT

BACKGROUND: The effects and mechanisms of bone morphogenetic protein 2 and basic fibroblast growth factor 2 on the proliferation and osteogenic differentiation of bone mesenchymal stem cells still remain unknown. How to combine the growth factors with tissue-engineered cell patch clamp techniques is of great significance for bone defect repair. OBJECTIVE: To explore the effects of bone morphogenetic protein 2 and basic fibroblast growth factor 2 applied alone or in combination on the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cell sheet. METHODS: Bone marrow mesenchymal stem cells from Sprague-Dawley rats were isolated, cultured and identified in vitro to construct cell sheet. Bone morphogenetic protein 2 and basic fibroblast growth factor 2 at different concentrations were individually or jointly used to induce bone marrow mesenchymal stem cell sheet. The cell counting kit-8 assay combined with alkaline phosphatase activity assay was used to determine the optimal concentration of the two factors in promoting cell proliferation and osteogenic differentiation. Osteogenic induction of bone marrow mesenchymal stem cell sheet was assessed by gross and microscopic observations, Vonkossa staining, alizarin red staining, and RT-PCR detection. RESULTS AND CONCLUSION: The single application of bone morphogenetic protein 2 enhanced the alkaline phosphatase activity of the bone marrow mesenchymal stem cell sheet, and the optimal concentration was 100 μg/L (P < 0.001). The single application of basic fibroblast growth factor 2 accelerated the proliferation of bone marrow mesenchymal stem cell sheet, and the optimal concentration was 20 μg/L (P < 0.001). Their combination facilitated the proliferation of the cell sheet, and boosted the alkaline phosphatase activities (P < 0.001). The four groups of cell sheet showed no significant morphological difference, and the osteogenic differentiation of the bone marrow mesenchymal stem cell sheet could all be induced through the osteogenic induction. Calcium nodules were most significant in the combination group (P < 0.001), suggesting that the combination significantly facilitated late osteogenic differentiation, suppressed early osteogenic differentiation of the sheet and showed significant synergistic effect (P < 0.001). In summary, the application of bone morphogenetic protein 2 combined with basic fibroblast growth factor 2 plays a synergistic role in promoting the proliferation of bone marrow mesenchymal stem cell sheet and significantly enhances the osteogenic induction.