Abstract:

BACKGROUND: When the complex was made, the seed cell’s vaccination density will affect the ability of the complex, but the appropriate incubation density was not still unified.
OBJECTIVE: To construct bone marrow mesenchymal stem cells (BMSCs)/bone matrix gelatin (BMG) complex and to observe the optimal cell density of BMSCs/BMG complex.
METHODS: BMSCs from Sprague Dawley rats were cultured in vitro. BMSCs at different cell densities were incubated on the heterogenic BMG. BMSCs/BMG complex was constructed, and the adherent growth of cells on the BMG was observed using scanning electron microscope. A bone defect model (5 mm in length) was created at bilateral radius in each Sprague Dawley rat. This study was divided into four groups. BMSCs/BMG complex was used to repair bone defect. The seeding density was respectively 1×108/L, 5×108/L, 1×109/L and 5×109/L. At 2, 4, 8 and 12 weeks, the samples were obtained in each group. Gross observation on the activity of operated limb, radiographic and histological examination and immunohistochemical analysis were performed to observe the repair condition of radius defect after surgery. 
RESULTS AND CONCLUSION: After 24 hours of BMSCs/BMG complex culture, the adherent rate of cells on the BMG increased with increased cell incubation density. When the densities surpassed 1×109/L, and the maximum adhesive rate was (76.00±2.94)%. Increased cell densities showed decreased adhesive rate. At day 7, results of scanning electron microscope exhibited cells adhered on the material. X-ray radiology score showed the score was greater at 8 and 12 weeks compared with that at 2 weeks in the same group (P < 0.01). No significant difference was determined at 4, 8 and 12 weeks in the 1×109/L and 5×109/L groups (P > 0.05), and the score was greater than other two groups (P < 0.01). Histological score results have demonstrated that the score was higher at 8 and 12 weeks than that at 2 weeks in the same group (P < 0.01). Results suggest that when constructing the BMSCs/BMG complex in vitro, the optimal BMSCs seeding density was 1×109/L.