Importance of the source of hyaluronidase preparations in determining protective effect on ischemic heart muscle in acute myocardial infarction

Using a very sensitive new technique, the effectiveness of hyaluronidase (HYL) in reducing infarct size (IS) was compared employing HYL obtained from bovine testicies and from fungi. One minute after coronary artery occlusion in dogs, highly radioactive microspheres were injected for autoradiographic assessment. The animals were then randomized into a control group and several HYL-treated groups. Six hours later all hearts were divided into 20 to 25, 3 mm-thick slices which were incubated in TTC to measure IS and thereafter autoradiographed to delineate the hypoperfused zone (HZ). The percent of HZ that evolved to necrosis (IS/HZ) was determined in each animal. In the control group, IS/HZ was 89.9 ± 4.2% and was reduced by 17% (p < 0.05) in the group treated with 500 units/kg of bovine HYL. With 500 units/kg of fungal HYL, IS/HZ was not reduced, but the higher dose of 5000 units/kg reduced IS/HZ by 26% (p < 0.01). Thus dependence of HYL source is documented relative to the effectiveness of this salutary intervention for protecting ischemic heart muscle and limiting necrosis in acute myocardial infarction.