Preventive effects of cyclosporin on diabetes in NOD mice.

Non-obese diabetic mice aged 30 to 60 days were treated orally with Cyclosporin at doses of 25, 15 and 2.5 mg/kg every 2 days until 160 days of age. Diabetes developed in 12 out of 18 oil-treated mice (67%), with partial to complete Langerhans' islet destruction associated with lymphocytic infiltration. The non-obese diabetic mice showed a plasma glucose concentration of 6.62 +/- 0.92 mmol/l (mean +/- SD) at 50 days of age. The plasma glucose level of oil-treated non-obese diabetic mice gradually increased after 130 days of age and reached 14.0 to 19.0 mmol/l at 160 days of age, while Cyclosporin-treated non-obese diabetic mice showed neither clear increase of plasma glucose levels nor development of insulitis. The cumulative incidence of diabetes in Cyclosporin-treated mice was significantly lower than that in oil-treated mice (p less than 0.01). Subsequently, Cyclosporin treatment was started after development of glucose intolerance. Twenty-five mg/kg of Cyclosporin was administered every 2 days for 35 days. Cyclosporin appeared to have little therapeutic effect on diabetes in non-obese diabetic mice.