TY - JOUR
T1 - Enhancement of recovery of myocardial function by oxygen free-radical scavengers after reversible regional ischemia
AU - Myers, M. L.
AU - Bolli, R.
AU - Lekich, R. F.
AU - Hartley, C. J.
AU - Roberts, R.
PY - 1985
Y1 - 1985
N2 - Reperfusion after reversible regional ischemia has been shown to result in delayed recovery of myocardial function, but the mechanism responsible for this phenomenon remains unknown. We explored the potential role of oxygen-free radicals as mediators of postischemic dysfunction in open-chest dogs undergoing a 15 min occlusion of the left anterior descending coronary artery (LAD) followed by 2 hr of reperfusion. Treated animals (n = 19) received an infusion of the oxygen free-radical scavengers superoxide dismutase (SOD; 15,000 U/kg) and catalase (CAT; 55,000 U/kg) for 1 hr starting 15 min before LAD occlusion, while control animals (n = 20) received an equal volume of saline. SOD and CAT produced no discernible effect on heart rate, aortic pressure, or left atrial pressure. Collateral flow to the ischemic zone (radioactive microspheres) was 0.07 ± 0.01 ml/min/g in both groups. The size of the occluded bed as determined by postmortem perfusion was 26.1 ± 1.2% of the left ventricle in the control group and 26.5 ± 0.9% in the treated group. Systolic wall thickening (an index of regional function) was assessed with an epicardial pulsed-Doppler probe. The two groups exhibited comparable systolic thickening under baseline conditions and similar degrees of dyskinesia during ischemia. Nevertheless, recovery of function (expressed as percent of baseline) was considerably greater in the treated dogs, both at 1 hr (43.8 ± 14.3 vs 12.8 ± 11.6) and 2 hr of reperfusion (74.2 ± 8.4 vs 31.6 ± 9.8, p < .005). This improved recovery of function obtained with SOD and CAT suggests that oxygen-free radicals play an important role in the genesis of myocardial dysfunction after a brief episode of regional ischemia.
AB - Reperfusion after reversible regional ischemia has been shown to result in delayed recovery of myocardial function, but the mechanism responsible for this phenomenon remains unknown. We explored the potential role of oxygen-free radicals as mediators of postischemic dysfunction in open-chest dogs undergoing a 15 min occlusion of the left anterior descending coronary artery (LAD) followed by 2 hr of reperfusion. Treated animals (n = 19) received an infusion of the oxygen free-radical scavengers superoxide dismutase (SOD; 15,000 U/kg) and catalase (CAT; 55,000 U/kg) for 1 hr starting 15 min before LAD occlusion, while control animals (n = 20) received an equal volume of saline. SOD and CAT produced no discernible effect on heart rate, aortic pressure, or left atrial pressure. Collateral flow to the ischemic zone (radioactive microspheres) was 0.07 ± 0.01 ml/min/g in both groups. The size of the occluded bed as determined by postmortem perfusion was 26.1 ± 1.2% of the left ventricle in the control group and 26.5 ± 0.9% in the treated group. Systolic wall thickening (an index of regional function) was assessed with an epicardial pulsed-Doppler probe. The two groups exhibited comparable systolic thickening under baseline conditions and similar degrees of dyskinesia during ischemia. Nevertheless, recovery of function (expressed as percent of baseline) was considerably greater in the treated dogs, both at 1 hr (43.8 ± 14.3 vs 12.8 ± 11.6) and 2 hr of reperfusion (74.2 ± 8.4 vs 31.6 ± 9.8, p < .005). This improved recovery of function obtained with SOD and CAT suggests that oxygen-free radicals play an important role in the genesis of myocardial dysfunction after a brief episode of regional ischemia.
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U2 - 10.1161/01.CIR.72.4.915
DO - 10.1161/01.CIR.72.4.915
M3 - Article
C2 - 4028384
AN - SCOPUS:0022411604
SN - 0009-7322
VL - 72
SP - 915
EP - 921
JO - Circulation
JF - Circulation
IS - 4
ER -