irisin levels increase during experimentally induced acute myocardial infarction

BACKgROunD: Irisin is a hormone involved in energy metabolism. To date, however, there are scant data regarding irisin levels in infarcted tissues. OBjECTIVE: To evaluate changes in irisin levels in the cardiac tissue of rats during experimentally induced myocardial infarction (MI). METhODS: A total of 21 rats, comprising three groups of seven animals each (MI-1, MI-2 and a control group), were used. Isoproterenol (150 mg/kg once daily for two days ) was used to induce acute MI. The rats in the MI-1 group were evaluated at the end of the first week after the development of MI; rats in MI-2 were evaluated at the end of the second week after the development of MI. Following decapitation, irisin levels in the removed cardiac tissue were examined using polymerase chain reaction and immunohistochemical methods. RESuLTS: Following Masson trichrome stain, irisin levels were found to be increased in the cardiac tissue of MI-1 and MI-2 rats compared with the control group. Furthermore, polymerase chain reaction findings demonstrated that messenger RNA levels of irisin increased by a mean (± SD) factor of 23.3±0.2 in MI-1 rats and 15.9±0.3 in MI-2 rats compared with the control group (P=0.001 for both groups). In addition, immunohistochemical methods revealed that the strength and prevalence of irisin immunoreactivity displayed a significant increase in MI-1 rats (+3 strength) and MI-2 rats (+2 strength) compared with the control group (+1 strength) (P=0.01). COnCLuSIOn: The present study demonstrated an increase in irisin levels in the cardiac tissue of rats with experimentally induced MI. Further studies will determine the significance of this increase in the pathogenesis of MI.