The effect of uraemia on organ graft survival in the rat.

A method of producing stable chronic renal failure in the rat is described. The animals show similar biochemical changes to uraemia in man but are not lymphopenic. Heterotopic cardiac allografts have been performed in inbred and outbred strains. Uraemia alone caused significant prolongation of survival of hearts from inbred August rats in inbred Wistar recipients. Azathioprine in a dose of 8 mg/kg/day produced marked prolongation of graft survival in uraemic animals but had no effect in normal animals. Hearts from outbred Wistar rats transplanted into outbred Wistar recipients showed a variable duration of survival, one graft surviving for 60 days. When outbred Wistar hearts were transplanted into outbred uraemic Wistar recipients 6 out of 13 grafts survived for more than 60 days. Histology of the long surviving hearts in uraemic animals showed slight cellular infiltration and most hearts showed intimal proliferation in arterioles. Histology of lymphoid tissue in uraemic animals showed no evidence of lymphocytic depletion. There was histological evidence of recirculation of lymphocytes through post-capillary venules in lymph nodes. There was no evidence of adrenal hypertrophy in uraemic animals as judged by weight and histological appearance.