Abstract: Objective: To evaluate the bone defect regeneration and repair ability of human bone marrow mesenchymal stem cells/extracellular matrix complex (C-BMSC). Methods: C-BMSC was constructed in vitro and examined by gross observation, HE staining, and scanning electron microscope (SEM). TUNEL staining was used to detect the level of apoptosis. The expression level of osteogenic related factors was detected by immunofluorescence staining and PCR. The rat skull defect model was used to evaluate the bone defect regeneration and repair ability of C-BMSC in vivo. Results: Histomorphology examination showed that the extracellular matrix (ECM) of C-BMSC was the most abundant in the 5-day group. The ECM completely wrapped the cells in C-BMSC. The ECM fibers were strong and small molecular substances were attached. TUNEL staining result showed that the number of apoptosis in the 3-day and 5-day groups was close, but it was increased significantly for the cell apoptosis level at 7-day (P<0.001). PCR results showed that the expressions of ALP, COL-1, Runx2, and OCN in C-BMSC was higher than those in BMSC-CS (P<0.05). Immunofluorescence results showed that ECM in C-BMSC was positive for ALP, COL-1, and BSP. C-BMSC also showed remarkable ability of bone tissue regeneration and repair in vivo (P<0.05). Conclusion: This study proves that C-BMSC has outstanding osteogenic differentiation ability, which provides a new strategy for bone defect regeneration and repair.

Key words: BMSCs, bone marrow mesenchymal stem cells/extracellular matrix complex, cell sheet, bone defect regeneration and repair