[Using perfusion bioreactor for mesenchymal stem cell proliferation in large tricalcium phosphate scaffold].

OBJECTIVE: To investigate the feasibility of using perfusion culture bioreactor for bone mesenchymal stem cell proliferation in large scale beta-tricalcium phosphate (beta-TCP) scaffold. METHODS: In the dynamic perfusion culture group, the porous beta-TCP cylindrical scaffolds combined with the sheep mesenchymal stem cells were continuously perfused with the complete alpha-MEM medium by a peristaltic pump for 1, 2 and 4 weeks. While in the static culture group, the hybrid constructs were immersed in the medium without perfusion for 2 and 4 weeks. The cell proliferation and distribution were examined by the daily glucose consumption, the cell viability and undecalcified histological study. RESULTS: The daily glucose consumption increased with time. The increase was much more evident in the first 2 weeks than in the last 2 weeks. The daily glucose consumption was higher in the dynamic culture group than in the static culture group. The cell viability also increased with time. It was higher in the dynamic culture group. In comparison to 2-week culture, the cell viability was significantly higher after 4-week culture in the dynamic culture group (P < 0.05), while it was not significantly different after 4-week culture in the static culture group (P > 0.05). Under dynamic perfusion culture, the mesenchymal stem cells survived and proliferated through the scaffolds. However, the mesenchymal stem cells survived and proliferated only in the peripheral pores of the scaffolds under static culture. Histomorphometrical study indicated that there were much more cells in dynamic culture group than in the static group. The cell/pore rate was not significantly different between 2-week static culture and 4-week static culture (P > 0.05). However, the cell/pore rate was significantly higher after 4-week dynamic culture than after 2-week dynamic culture (P < 0.05). CONCLUSION: Perfusion culture permitted the persistent nutrition supply and gas exchange into the centre of large scaffold. This perfusion bioreactor makes the mesenchymal stem cells survive and proliferate through a large three-dimensional scaffold.