Insulin treatment prevents vascular dysfunction in early juvenile alloxan-induced diabetes mellitus

Microvascular pathology and sympathetic autonomic dysfunction have been described early in alloxan-induced diabetic juvenile rats. To determine the longitudinal development of these changes and whether insulin treatment can alter them, vascular and sympathetic function were studied in alloxan-induced (42.5 mg/kg) juvenile diabetic rats and saline-treated controls. The rats were examined 1 and 14 days after induction of diabetes. An insulin-treated group was studied with the 14-day group. Hindquarter perfusion with an artificial solution at constant flow/100 g hindquarter wt was used. After 14 days of diabetes mellitus, the diabetic group showed a significantly depressed response to central ischemia (P less than 0.001), maximal vasoconstriction (P less than 0.02), and maximal dilation (P less than 0.001) compared with both the control and insulin-treated group. The threshold response to norepinephrine did not differ. After 1 day of glucose elevation no differences were present between the control and diabetic animals during any of the testing procedures. These results suggest that severe vascular dysfunction develops early in juvenile-onset alloxan diabetes and that it can be prevented with insulin treatment.