Fig. 4.

Histopathological staining of the repair tissue at 2 weeks after surgery

Sagittal sections of full-thickness articular cartilage defects in the loading group (A, B) and unloading group (C, D). The articular cartilage defect is located in the center of the femur. The sections are stained with hematoxylin and eosin (A, C) and with toluidine blue (B, D). In the hematoxylin and eosin staining, the defects are filled with a mixture of granulation tissue and some remnants of the hyaline cartilage. The invasion of blood vessels and the presence of fibroblasts are observed in the repair tissue. In the toluidine blue staining, both groups tend to show no or little staining. Scale bar = 500 µm.