Scavenging effect of nicorandil on free radicals and lipid peroxide in streptozotocin-induced diabetic rats

Free radicals and lipid peroxide (LPO), easily formed in the diabetic state , play an important role in the development of diabetic complications. Pote ntially, nicorandil may reduce the production of free radicals and LPO in v arious organs. In fact, increased LPO levels in the serum, kidney, and card iac muscle of diabetic (DM) rats were reduced by nicorandil treatment (N tr eatment). Xanthine oxidase (XOD), which produces free radicals, was decreas ed in the liver and increased in the kidney of DM rats compared with contro l rats, and these changes were prevented by N treatment. The concentration of Cu, Zn-superoxide dismutase (SOD) decreased in the cardiac muscle and in creased in the kidney of DM rats, and these changes returned to normal afte r N treatment. The decreased concentration of Mn-SOD in the liver, kidney, and cardiac muscle from DM rats was also reversed by N treatment. The chang es in catalase and glutathione peroxidase (GSH-PX) activities in DM rats we re not improved effectively by N treatment. Another K-adenosine triphosphat e (K-ATP) channel opener, tilisolol hydrochloride, had an effect similar to that of nicorandil. The effects of nicorandil and tilisolol were studied o nly in DM rats. These data imply that N treatment, as an antioxidative ther apy, may be beneficial in preventing diabetic complications due to lipopero xidation and free radicals in DM rats. Copyright (C) 2000 by W.B. Saunders Company.