Experimental studies on vascularized allogeneic joint transplantation in rats

: Examination was made on the effects of Cyclosporine A, an immunosuppressive drug, on vascularized joint allografts. Genetically inbred DA and Lewis rats were used and a model of knee joint orthotopical transplantation across the major histocompatibility barrier was developed. Nine non-immunosuppressive allografts failed to acquire bony union. Twenty-seven short term immunosuppressive rats acquired solid union, but following withdrawal of immunosuppression, the grafts were soon rejected and joint function was lost due to pathological fractures of the grafted bone or joint instability. Thirteen allografts of continuous immunosuppression at a dose of 5 mg/kg/day showed no rejection, though the bone marrow did, and there was no impairment of function. The continuous administration of low and non-toxic dose of Cyclosporine A was necessary for maintaining grafted joint functions.