Cyclosporin prevents diabetes in BB Wistar rats.

Cyclosporin (U.S.A.N. cyclosporine) was used prophylactically to suppress the development of insulin-dependent diabetes mellitus in BB Wistar rats. In this rat strain diabetes spontaneously develops between 60 and 120 days of age and this condition resembles human type 1 diabetes. In 30 (75%) out of 40 control rats glycosuria and hyperglycaemia developed and these rats became insulin-dependent. Their pancreases showed partial to complete destruction of the islets of Langerhans by lymphocytic infiltration. None of the 40 cyclosporin-treated rats became diabetic and their pancreases were histologically normal. Serum cyclosporin was monitored in a subgroup and the dosage was adjusted accordingly; neither hepatotoxicity nor nephrotoxicity was seen in the treated animals.