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Title: Protective effect of PEG-SOD against early coronary reperfusion injury assessed in reperfused and non-reperfused ischaemic areas of the same heart
Author(s): KANAMASA, Ken , ISHIDA, Norihiro , ISHIKAWA, Kinji
Journal: Acta Cardiologica
Volume: 56 Issue: 3 Date: June 2001
Objective — In order to investigate the salvage of ischaemic myocardium by polyethylene glycol- conjugated superoxide dismutase (PEG-SOD),we compared reperfused and non-reperfused regions in the same canine heart and measured regional myocardial blood flow (RMBF) and myocardial CPK during coronary occlusion and reperfusion using non-radioactive, coloured microspheres.
Methods and results — The chests of 17 mongrel dogs were opened under anaesthesia, and the left circumflex coronary artery was occluded for 90 min and then reperfused for 5 min.During this procedure, polystyrene microspheres of different colours were infused at four different times:prior to occlusion (orange), 10 min (red) and 90 min (blue) after occlusion, and 5 min after reperfusion (yellow). Thereafter, the heart was excised, cut in slices along the left circumflex coronary artery, and flow rates at the various times were assessed as a function of microsphere counts. In the control group (n=9), there are significant differences in the myocardial CPK level between reperfused and non-reperfused areas.The myocardial CPK level in reperfused area was significantly reduced compared to non-reperfused area in the outer layers (54 ± 8 IU/g vs. 74 ± 9 IU/g, P<0.05), and also reduced in the inner layers (59 ± 9 IU/g vs.74 ± 13 IU/g),however,it was not significantly different. In the PEG-SOD group (n=8),there was no significant difference in the myocardial CPK level between reperfused and non-reperfused areas in both inner and outer layers (inner layers; 68 ± 11 IU/g vs. 68 ± 6 IU/g, outer layer; 69 ± 17 IU/g vs. 67 ± 18 IU/g), indicating a significant protective effect of PEG-SOD. In the control group, transmural necrosis of the reperfused areas was 22.4 ± 10.0%, which showed no significant difference compared with non-reperfused areas (23.1 ± 9.9%). In the PEG-SOD group,transmural necrosis of the reperfused areas by TTC staining was 8.1 ± 8.1%,which showed no significant difference compared with non-reperfused areas (8.5 ± 7.1%).
Conclusions — PEG-SOD prevents infarct extension during early coronary reperfusion.