Renalase protects the cardiomyocytes of Sprague-Dawley rats against ischemia and reperfusion injury by reducing myocardial cell necrosis and apoptosis.

BACKGROUND/AIMS Renalase, a novel flavoprotein expressed in the kidney and heart, reduces renal tubular necrosis and apoptosis, which suggests that it might protect against necrosis and/or apoptosis in myocardial ischemia reperfusion injury (MIRI). The present study thus explored the effects of renalase on Sprague-Dawley (SD) rats subjected to MIRI. METHODS We used Lentivirus-mediated RNA interference (RNAi) to inhibit the renalase gene expression in the heart tissue via pericardial cavity injection. The MIRI animal modal was established by blocking the left anterior descending artery for 45mins followed by 4h of reperfusion. Real-time PCR and western blotting were used to detect renalase expression in the heart tissue. Double staining and TUNEL were used to detect the necrosis and apoptosis in the myocardial cells, respectively. RESULTS All rats subjected to MIRI exhibited lower levels of renalase in the heart tissue than did the sham-operated group (P<0.05, n=6). The (RNAi) group rats exhibited lower renalase levels than did the controls and also exhibited more serious necrosis (7.12±0.56% vs. 3.32±0.93%, P<0.05, n=6) and apoptosis (151.8±8.2% vs. 66.8±6.5%, P<0.05, n=6); however, pretreatment with the recombinant renalase significantly reduced myocardial cell necrosis (1.51±0.12% vs. 4.13±0.02%, P<0.05, n=6) and apoptosis (21.3±5.0% vs. 52.6±10.4%, P<0.05, n=6) relative to the control rats. CONCLUSIONS Exogenous recombinant renalase protein reduced myocardial cell necrosis and apoptosis. Recombinant renalase protein might be a new cardiovascular drug for ischemia/IR injury.