Mitochondrial proteome analysis reveals depression of the Ndufs3 subunit and activity of complex I in diabetic rat brain.

Type-1 diabetes resulting from defective insulin secretion and consequent hyperglycemia, is associated with "diabetic encephalopathy." This is characterized by brain neurophysiological and structural changes resulting in impairment of cognitive function. The present proteomic analysis of brain mitochondrial proteins from streptozotocin-induced type-1 diabetic rats, shows a large decrement of the Ndufs3 protein subunit of complex I, decreased level of the mRNA and impaired catalytic activity of the complex in the diabetic rats as compared to controls. The severe depression of the expression and enzymatic activity of complex I can represent a critical contributing factor to the onset of the diabetic encephalopathy in type-1 diabetes.