Intra-articular injection of optimal concentrationof bonemarrowmesenchymal stem cells for treating rabbit cartilage defects / 中国组织工程研究

ABSTRACT

BACKGROUND: Bone marrow mesenchymal stem cells have been extensively applied in animal experiments and clinical studies. The cell concentration, treatment times and results in each study are different, and there is no standard for optimal cell concentration. OBJECTIVE: To investigate the optimal concentration of bone mesenchymal stem cells injected into articular cavity in the treatment of rabbit cartilage defects. METHODS: Thirty 6-month-old New Zealand white rabbits were selected and randomly divided into control, 1×108, 1×109, 1×1010, and 1×1011/L groups. Cartilage defect models with diameter of 3 mm and depth of 2 mm were established in femoral trochlea in each group. One week after modeling, 1 mL of normal saline was injected into the rabbit’s knee of the control group. The other groups were injected with bone marrow mesenchymal stem cells at corresponding concentrations. After 6 and 12 weeks, gross observation, hematoxylin-eosin staining, Safranin-O-fast green-staining, type I and II collagen staining were performed to assess the cartilage regeneration. RESULTS AND CONCLUSION: In the control group, the defect area was obvious with no cartilage regeneration. The 1×108, 1×109, and 1×1010/L groups showed cartilage regeneration. The repairing effect was increased with the cell concentration increasing. The effect of cartilage repair in the 1×1011/L group was similar to that in the 1×1010/L group (P > 0.05). Therefore, 1×1010/L is the optimal concentration for intra-articular injection of bone marrow mesenchymal stem cells for treating cartilage defects, and higher concentration cannot enhance the repairing effect.