Fig. 1

Histological features of femoral articular cartilage. The changes were observed after immobilization and intra-articular administration of blood (Im-B) or normal saline (Im-NS) from 3 days to 8 weeks. Upper row (a-h) showing the changes in cartilage in the contact area. Cartilage degeneration and decreasing number of chondrocytes gradually progressed after immobilization. Degeneration of the non-contact area is shown in the lower row (i-p). Although similar cellularity was observed in the contact and non-contact areas, cartilage degeneration was milder in the non-contact areas. Hematoxylin and eosin staining. The white arrows indicate the swelling of chondrocytes and the black arrows indicate the disappearance of the cells. The white arrowheads indicate cells with decreased cell staining intensity. The black arrowheads indicate cloning cells. Scale bar = 50 μm