NEUTROPHIL-INDEPENDENT MYOCARDIAL DYSFUNCTION DURING AN EARLY-STAGE OF GLOBAL-ISCHEMIA AND REPERFUSION OF ISOLATED HEARTS

The effect of global ischemia and reperfusion on the expression of cyt okine genes and cell adhesion molecules by myocardial tissues and neut rophils was studied by using the Langendorff model. Although cardiac f unction deteriorated after reperfusion of ischemic hearts, there was n o evidence of inflammation and myocardial degeneration, which is in co ntrast to previous findings that neutrophil-mediated inflammation is a critical step in post-ischemic reperfusion injury in regional ischemi a. Flow cytometry analysis demonstrated that the global ischemia and r eperfusion did not affect the expression of adhesion molecules on neut rophils. We also examined the expression of various cytokines which ar e involved in inflammatory responses. Only interleukin 1 alpha was ind uced after the reperfusion of the ischemic hearts. These results sugge st that neutrophils barely contribute to the myocardial dysfunction an d IL-1 alpha may play a role in post-ischemic myocardial dysfunction d uring the early stage of reperfusion.