EFFECTS OF HYALURONIDASE ON REDUCING MYOCARDIAL INFARCT SIZE IN A BABOON MODEL OF ISCHEMIA-REPERFUSION INJURY

Hyaluronidase has been reported to be beneficial in reducing injury to the ischemic myocardium in several experimental studies. This effect may involve an enhancement in either the cardiac blood supply or lymph atic flow or a combination there of. In this experiment, a baboon open chest model of myocardial ischemia and reperfusion was used to determ ine if treatment with hyaluronidase would result in a reduction in inf arct size. Baboons underwent occlusion of the left anterior descending coronary artery for 2 hr. Fifteen minutes after occlusion, a treated group (n = 6) received bovine testicular hyaluronidase (500 national f ormulary units/kg) iv over a 1.0-min period. The ischemic period was f ollowed by 22 hr of reperfusion. A control group (n = 8) underwent the same protocol minus the hyaluronidase infusion. At the end of the rep erfusion period, the hearts were excised and the perfusion bed at risk for infarction was determined by the infusion of a microvascular dye. The hearts were then sectioned and stained for the histological deter mination of infarct size. The volume of the perfusion bed infarcted wa s 66 +/- 7% in the control group compared with 42 +/- 10% in the treat ed group (P > 0.05). In this study using a primate model that has a mi nimal collateral blood supply, hyaluronidase did not significantly red uce the ultimate infarct size. (C) 1995 Academic Press, Inc.