Oxygen free radicals and their metabolites have been implicated as possible causes of reperfusion injury in animal models. Their role in the clinical setting is still controversial. The aim of this study was to evaluate the degree of tissue
damage,
oxidative stress and changes in the antioxidant enzyme system in patients undergoing coronary artery bypass graft operations(CABG) with myocardial protection by cold blood cardioplegia.
In patients undergoing CABG(n=10), the levels of lactate dehydrogenase(LDH). Creatine phosphokinase MB fraction(CK-MB), and malondialdehyde(MDA) were measured in the coronary sinus effluent before aortic cross clamping and 20 minutes after
reperfusion.
At the same time, the myocardial tissue activities of superoxide dismutase(SOD), catalase(CAT), glutathione peroxidase(GSHPx), glutathione reductase (GSSGRd), and glucose 6-phosphate dehydrogenase(G6PDH) were determined in the right atrial
auricle
excised before aortic cross clamping and in the left atrial auricle excised 20 minutes after reperfusion.
The levels of LDH(268±40.3 to 448±84.9 U/ml plasma). CK-MB(4.50±2.33 to 27.1±13.5 U/ml plasma), MDA(5.87±2.02 to 10.5±2.23 nmol/mo plasma), SOD(13.5±4.04 to 20.7±8.56 U/mg protein). GSHPx(279±37.2 to 325±51.4 U/mg protein) and
GssGRd(97±15.9
to 122±25.1 mU/mg protein). Increased significantly after reperfusion(p<0.05). There were no significant changes in CAT and G6PDH level. Western blot analysis was performed to study the induction of antioxidant enzyme and demonstrated increased
amount
of Cu, Zn-SOD.
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