Antioxidants attenuate diabetes-induced activation of peroxisomal functions in the rat kidney

Diabetes is a multifactorial disease that has now been recognized to involve overproduction of reactive oxygen species and pro-inflammatory cytokines. Peroxisomes are subcellular organelles with several important metabolic functions, and their role in the regulation of cellular oxidative stress is now well established. Despite having their own antioxidant system, peroxisomes undergo functional alterations during various conditions that are associated with free radical production such as inflammation, ischemia-reperfusion, carcinogenesis and diabetes. In this study we investigated the effect of diabetes on peroxisomal functions in rat kidneys and show for the first time that experimental diabetes induces redox-sensitive enhancement of peroxisomal activities. Streptozotocin-induced diabetes significantly increased (p < 0.01) beta-oxidation of lignoceric acid and the enzymic activity of acyl coenzyme A oxidase. Catalase activity was significantly reduced (p < 0.01) in the kidneys of diabetic rats, whereas the enzymic activity of DHAPATase (dihydroxyacetone phosphate acyltransferase) was not markedly affected by diabetes. Treatment of diabetic rats with antioxidants, thiocetic acid and vitamin C attenuated the diabetes-induced modulation of peroxisomal functions. The present study shows that the diabetes-induced effects on kidney peroxisomal functions are redox sensitive, and antioxidants might prove useful tools to alleviate nephropathy in diabetes.