[Fresh allograft of intact growth plate into immature articular cartilage defects in rats]

In three inbred rat strains with a distinct major histocompatibility complex (MHC), MHC-matched allografts (Fisher, RT1l to Lewis, RT1l, n = 39) or MHC-mismatched allografts (Brown Norway, RT1n to Lewis, RT1l, n = 38) of fresh intact cartilage obtained from the tibial epiphyseal growth-plate were grafted into the defects in the femoral articular surface of immature rats. In the controls (n = 72), similar defect on the joint cartilage were made with no epiphyseal plate grafts. The present histological observation was continued throughout one year after transplantation. Total success rate of the repair was significantly better in MHC-matched allografts (92%) than in MHC-mismatched allografts (61%, p less than 0.001) or controls (19%, p less than 0.001). The MHC-matched allografts showed no signs of tissue rejection. However, the MHC-mismatched allografts showed evidence of lymphocyte infiltration and 13 (81%) of 16 grafts were rejected from 12 to 48 weeks after operation. These findings indicate that MHC-matched allografts of intact growth-plate have a potential to repair defects in immature articular cartilage over a long period of time, but MHC-mismatched allografts will eventually be rejected.