Apoptosis of Cardiomyocytes Assessed by a Novel Apoptotic Marker (Annexin V) and the Role of Vitamin E in Cardioprotection in Diabetic Rats
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- Category: Vol. 77, March 2009
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Apoptosis of Cardiomyocytes Assessed by a Novel Apoptotic Marker (Annexin V) and the Role of Vitamin E in Cardioprotection in Diabetic Rats,
OLA M. TORK and ABDELKARIM KAMEL
Abstract
Background: Recently it has been shown that annexin V is an apoptotic marker in the heart. The aim of the present study was to explore whether annexin V content in the heart changes during diabetes in order to use it as a prognostic factor in diabetic cardiac affection. In addition, the study attempted to show the effect of treatment of insulin and vitamin E (300mg and 600mg/Kg) used separately or in combination.
Methods: The study included 70 male albino rats weighing 170-200gm. They were divided into the following groups of 10 rats each: Group I (cont): Control group, Group II (DM): Diabetic, untreated group. Diabetes was induced by intraperi-toneal injection of streptozotocin (stz) at a dose of 40mg/kg body weight, Group III (Ins): Diabetic group, treated with 1 unit insulin injected subcutaneously, Group IV (E-300): Diabetic group, receiving 300mg/kg vitamin E injected intra-muscularly, 3 times/week for one month, Group V (E-600): Diabetic group, receiving vitamin E i.m injection at a dose of 600mg/kg, 3 times/week for one month, Group VI (I+E-300): Diabetic group treated with insulin and vitamin E (300mg/kg/dose) and Group VII (I+E-600): Diabetic group treated with insulin and vitamin E (600mg/kg/dose). Annexin V and inducible nitric oxide synthase (iNOS) were examined in the hearts of animals by RT-PCR. Also, cGMP, malondial-dehyde (MDA), glutathione peroxidase (GPX) and cardiac enzymes were measured.
Results: There were three major new findings in the present study. First; annexin V levels were significantly elevated in the heart of diabetic rats compared to controls. This elevation in annexin V content indicates that apoptosis is the basis of cardiac injury as shown by the elevated cardiac enzymes AST, ALT & CPK. Second, levels of iNOS protein of the heart were elevated in diabetic rats. On the basis of theses findings, we can suggest that inflammation could play a role in the pathogenesis of diabetic cardiomyopathy in type 1 diabetes. Third, the effect of various types of treatment of diabetes which were used here showed the beneficial effects of the use of the antioxidant, vitamin E.