Cell tracking. HDMACs made with labeled MSCs were implanted to the osteochondral defect. The labeled cells were detected as chondrocytes in the cartilage and osteocytes in the subchondral bone 6 weeks after implantation, suggesting that the implanted MSCs had spontaneously differentiated into chondrocytes or osteocytes in accordance with their implanted positions. Scale bar = 200 μm. (N = 1).