RESUMO
BACKGROUND: The application of mesenchymal stem cells (MSCs) in the treatment of cartilage damage has become a hot spot of research. Further studies on the distribution of MSCs in the body after injection and on the underlying mechanism of action are needed. OBJECTIVE: To observe the migration of bone marrow mesenchymal stem cells (BMSCs) after injection into the region of osteochondral defect. METHODS: Thirty Sprague-Dawley rats were randomized into two groups (n=15 per group). In the control group, the femoral tochlear was exposed but an osteochondral defect was not made; and after the suture, PKH26-labeled BMSCs were directly injected into the articular cavity of rats. In the experimental group, a cartilage defect of 1 mm in diameter and 1 mm in depth was made in the rat femoral trochlea, and 5×106PKH26-labeled BMSCs were injected into the defect after operation. At 1, 3 and 7 days after injection, the femoral condyle was taken to make frozen sections followed by DAPI staining. The distribution of BMSCs was observed under laser scanning confocal microscope. RESULTS AND CONCLUSION: In the control group, PKH26-labeled BMSCs were not transferred to the subchondral bone. In the experimental group, BMSCs were detected in the subchondral bone area at 1, 3 days after injection of PKH26-BMSCs in the bone cartilage defect area, and the BMSCs were also found in the bone marrow cavity at 7 days after injection. In conclusion, BMSCs in the articular cavity cannot migrate into the subchondral bone and bone marrow cavity unless the cartilage of the femoral condyle is damaged.