[Research of osteoblast-induced rat mesenchymal stem cells cocultured with beta-TCP/PLLA composite of different ratio]

There are three key factors in tissue engineering: seeding cells, scaffold and their interaction. Although mesenchymal stem cells (MSCs) are potential seeding cells, the problem of what phase MSCs should be used is not yet solved. On the other hand, degradable porous scaffolds which have good mechanics and good biocompatibility are preferred. To choose the optimum seeding cells and the suitable ratio of beta-TCP/PLLA porous scaffold, we observed the phenotype of the male SD rat's osteoblastic MSCs and detected the amount of alkaline phosphatase, osteocalcin and type I collagen secreted by the osteoblastic rMSCs in different phase. About 10, 14 and 20 days after induction, the induced cells came into proliferative phase, matrix synthesis phase and mineralization phase, respectively. Then we chose the suitable cells and seeded them on beta-TCP/PLLA composite scaffolds with different ratios (beta-TCP/PLLA = 1:1; beta-TCP/PLLA = 1:2; and beta-TCP/PLLA = 2:1). Fluorescence microscope, scanning electron microscope and MTT assay were used to observe and to detect the biocompatibility of the scaffolds. The results indicated that all of these materials have biocompatibility to some extent. Cells can grow well on all of the scaffolds. However, scaffold beta-TCP/PLLA = 2:1 seems to be a more suitable tissue engineering scaffold on account of its minimal influence on cell growth and differentiation.