The Lipid Peroxidation During Cardiopulmonary Bypass In The Children With Congenital Heart Diseases And The Therapeutic Effect Of N-acetylcysteine

Objective:To evaluate the protective effect of N-acetylcystein(NAC) against myocardial ischemia-reperfusion injury during cardiopulmonary bypass in infants with congenital heart disease,by exploring the changing of 8-iso-prostaglandin F2α(8-iso-PGF2α) as well as myocardial enzymes and the transformation of myocardium ultrastructure,in order to provide a new method for prevention and cure of the lipid peroxidation damage at CPB stage.Method:30 patients with congenital heart disease were randomly divided into 2 groups. NAC was administered to observing group but not to controls before operation in protocol of 10mg/kg PO every 12 hours for 6 doses.Peripheral blood specimens for detection of 8-iso-PGF2α,creatine kinase(CK) and CK-MB were collected after admittance to hospital(T₀),before cardiopulmonary bypass(T₁),15 minutes after aortic clamping(T₂) and 30 minutes after aortic repatency(T₃).Myocardium tissues were sampled at T₃ for electromicroscope observation.Postoperative dopamine usage, cardioversion rate,mechanical ventilation time and intensive care unit(ICU) hospitalization period were recorded and analyzed.Result:The levels of 8-iso-PGF2α,CK and CK-MB at T₂ and T₃ are significantly higher than those at To and T₁ both in 2 groups.8-iso-PGF2α,CK and CK-MB concentrations at T₂ and T₃ were lower in observing group than in controls,while no significances were found between 2 groups at T₀ and T₁.Myocardium ultrastructural impairment,including myofibrillar and mitochondrial degeneration,in observing group was minor compared to controls.Postoperative dopamine usage,cardioversion rate,mechanical ventilation time and ICU hospitalization period had no significant differences in 2 groups.Conclusion:Myocardial isehemia-reperfusion during cardiopulmonary bypass could lead a lipid peroxidation impairment in CHD children,which was shown by the rising levels of 8-iso-PGF2αand myocardial enzymes,as well as the damage of myocardial ultrastructure.That NAC preconditioning decreases the release of myocardial enzymes and concentrations of 8-iso-PGF2αsuggests that it may protect myocardial mitochondrion from ischemia-reperfusion damage during open heart surgery with CPB.