Effects of acute exercise on hypoxia-reoxygenation injury in adult rat heart

Abstract

Some reports demonstrated that heat shock proteins (HSPs) contribute to cardio-protective effects against the ischemia-reperfusion injury. However, it has been studied that cardiac function decreases after acute endurance exercise (EEx) in human heart. These inconsistent results may be caused due to HSPs cannot produced in acute EEx. Therefore, we studied by using Langendorff-perfused heart model if HSPs are inducted by acute EEx and if they contribute to cardio-protective effects against hypoxia-reoxygenation (H-R) injury. Male Wistar rats (280-320g) were randomly assigned to either a control (CON) group or an acute EEx (3D) group (n=8/group). 3D animals performed 60 minutes treadmill running (–20 m/min) for 3 days consecutively. Although cardiac HSP72 increased significantly in 3D group, pressure-rate product of hearts at 30 minutes reoxygenation did not differ from CON group. In addition, the incidence rate of ventricular fibrillation or tachycardia in 3D group significantly increased compared with CON group (50% vs 13%, p<0.05). These results suggest that the acute EEx may cause cardiac dysfunction regardless of EEx-induced HSP72 in rat. [J Physiol Sci. 2008;58 Suppl:S187]