PKC β inhibitor ruboxistaurin prevents the increase of 15-F2t-isoprostane in the myocardium and plasma in Type 1 diabetic rats

Abstract

Levels of 15-F2t-isoprostane (IsoP), a specific marker of oxidative stress and a recently identified independent predictor of myocardial morbidity in patients with ischemic heart disease, are increased in the myocardium and plasma in Type 1 diabetes. The beta isoform of Protein kinase C (PKCβ) is over-expressed in the myocardium of diabetic rodents and contributes to the development of diabetic cardiomyopathy and associated complications. We postulated that selective PKCâ inhibition with ruboxistaurin would attenuate hyperglycemia-induced oxidative stress and normalize IsoP production. Control or streptozotozin-induced diabetic rats were treated (DT) or untreated (C, D) with ruboxistaurin (1 mg/kg/day) delivered by oral gavage for four weeks. Myocardial IsoP content, cardiac mass and plasma IsoP were significantly increased while there was a significant decrease in superoxide dismutase activity in D compared to C rats (all P<0.05). Ruboxistaurin treatment normalized all these changes. It is concluded that ruboxistaurin may have prevented hyperglycemia-induced oxidative stress by restoring endogenous antioxidant enzyme superoxide dismutase activity in diabetes.