Modulation of oxidative stress by enalapril and valsartan in adrenaline treated rats: a comparative study.

Angiotensin (Ang II) II is known to promote oxidative stress in acute myocardial infarction (AMI). Inhibition of renin angiotensin system (RAS) or blockade of Ang II receptors may therefore be effective in reducing oxidative stress during AMI. The study evaluates and compares the protective effect of Angiotensin Converting Enzyme (ACE) inhibitor and AT1 receptor blocker in adrenaline induced oxidative stress in rats. Rats were treated with two successive injections of adrenaline subcutaneously at a dose of 2 mg/kg administered 24 hours apart. In other two groups of rats enalapril (30 mg/kg) or valsartan (30 mg/kg) were given orally once daily through intragastric tube for 2 weeks and then two injections of adrenaline were administered 24 hours apart. Serum Aspertate Transaminase (AST), plasma Malonde Aldehyde (MDA), erythrocyte GSH and serum vitamin E levels were measured 24 hours after the 2nd injection of adrenaline in all the groups. Administration of adrenaline caused significant increase (p < 0.001) in serum AST and plasma MDA levels and decrease (p < 0.001) in erythrocyte GSH and serum vitamin E levels. Pre-treatment of enalapril or valsartan for 14 days reduced (p < 0.001) serum AST and plasma MDA levels and increased the concentration of erythrocyte GSH in enalapril pre-treated group (p < 0.01) and in valsartan pre-treated group (p < 0.05). Pre-treatment of enalapril or valsartan also increased (p < 0.01) serum vitamin E levels in adrenaline treated rats. However, no significant difference was noted between the effect of enalapril and valsartan on serum AST, plasma MDA, erythrocyte GSH and serum vitamin E levels. It may be concluded that both enalapril and valsartan offered cardioprotection in adrenaline induced oxidative stress, but the protection afforded by valsartan was not superior to enalapril.