Effect of lipoic acid on cyclophosphamide-induced diabetes and insulitis in non-obese diabetic mice.

In an animal model of type I diabetes, the non-obese diabetic (NOD) mouse, the influence of the antioxidant lipoic acid (LA) on the development of diabetes was investigated. Acceleration of diabetes development with cyclophosphamide (CY) resulted in 60% diabetic animals with severely infiltrated islets within 1-3 weeks. Daily administration of lipoic acid for 20 or 30 days around cyclophosphamide treatment suppressed the incidence of diabetes to 30% (P < 0.05) and 33%, respectively. Semiquantitative analysis of islet infiltration showed a reduction of severe intraislet infiltration and an increase in the percentage of islets with mild per-insular and periductular infiltrates (from 8.4 to 29.6 and 25.9%, respectively, P < 0.01) after lipoic acid treatment. These results show that the protective effect of lipoic acid on diabetes development correlates with partial suppression of islet inflammation. The anti-inflammatory action of lipoic acid may be due to its ability to scavenge oxygen radicals and to suppress nitric oxide production.