Effects of human urotensin II on ischemia/reperfusion injury in isolated perfused rat hearts

AIM: To investigate the effects of human urotensin II (hUII) on ischemia/reperfusion (I/R) injury in isolated rat hearts. METHODS: In the ischemia/reperfusion (I/R) model of isolated perfused rat hearts, the effects of hUII pretreatment on cardiac function was monitored with cardiac function software of MFL Lab200. ATP, total calcium, and malondialdehyde (MDA) content in myocardium were detected. The coronary perfusion flow (CPF) and lactate dehydrogenase (LDH) activity in coronary effluent were measured during reperfusion. RESULTS: In the hUII pretreated group, the release of LDH from myocardium was lower (78.3±18.1)U/L] than I/R group (109.3±23.9) U/L, P< 0.05], with decreased contents of MDA and calcium in myocardium (decreased by 24% and 27%, respectively, P< 0.05) and an increased myocardial ATP content (3.8±0.4)μmol/g dw vs (2.2±0.4)μmol/g dw, P< 0.05)]. At the same time, hUII pretreatment increased CPF (5.4±0.7) mL/min vs (3.8±0.8) mL/min in I/R group, P< 0.05], reduced left ventricular end-diastolic pressure (LVEDP) by 20% ( P< 0.05) with increased±d p /d t max (217±38) kPa/s and (119±18) kPa/s vs (173±29) kPa/s and (82±25) kPa/s in I/R groups, respectively, P< 0.05]. hUII pretreatment also increased natrite/natrate (NO₂^-/NO₃^-) content in coronary effluent (52.2±12.0)μmol/L vs (32.1±10.2)μmol/L in I/R group, P< 0.05)]. CONCLUSION: hUII pretreatment attenuated I/R injury in isolated perfused rat hearts. The protective mechanism might be associated with NO-mediated coronary vasodilation.