ABSTRACT
Recently, urea is considered one of the endogenous antioxidant substances that have a potential antioxidant cardioprotective effect against ex vivo post-ischemic reperfusion and oxidative stress induced cardiac injury in rats. A single injection of doxorubicin, 15 mg Kg[-1], intrapeirtoneal [i.p] in rats induced cardiac toxicity manifested biochemically by the significant increase [P<0.01] of serum creatine phosphokinase [CPK] and lactate dehydrogenase [LDH] after 48 hours and significant decrease [P<0.01] of heart homogenate superoxide dismutase [SOD] and reduced glutathione [GSH] compared to normal control rats. Administration of urea [500 mg Kg[-1] day[-1] i.p] for 2 successive days improved doxorubicin induced cardiotoxicity in rats represented by the significant decrease [P<0.01] of serum CPK and LDH in comparison to rats injected with doxorubicin only. The cardioprotective effect of urea could be explained by the observed significant reduction [P<0.01] of heart homogenate lipid peroxidation, expressed as thiobarbituric acid reacting substances [TBARS], and significant increase [P<0.01] of SOD and GSH compared to doxorubicin-induced cardiotoxicity rats. In conclusion, urea could have antioxidant cardioprotective effect in vivo against acute doxorubicin-induced cardiotoxicity. This newly observed effect of urea might have broad applications towards many oxidative stress-related pathophysiological situations