St.Thomas液中加入N-乙酰半胱氨酸可减轻幼兔心肌的缺血再灌注损伤

Protective effects of N-acetyl-L-cysteine on hypothermic ischemia reperfused isolated immature rabbit hearts

目的 观察附加 0 .4mmol/LN 乙酰半胱氨酸 (NAC)心脏停搏液 (NAC组 )和St .Thomas液 (ST组 )对低温缺血再灌注幼兔心肌的保护作用。方法 采用Langendorff Neeley离体左心做功模型 ,离体心脏缺血液 12 0min ,再灌注 6 0min ;分离出缺血再灌注幼兔左室心肌肌浆网 ,测定其总巯基 (TSH)、非蛋白巯基(NPSH)、丙二醛 (MDA)及Ca2 + ATP酶活性。结果 NAC组 ,再灌注后心脏功能恢复明显优于ST组 ;TSH ,NPSH含量明显高于ST组 ,同时MDA含量明显低于ST组 ;NAC组缺血再灌注对肌浆网Ca2 + ATP酶活性的抑制较ST组轻。结论 附加NAC可显著改善St .Thomas液对低温缺血再灌注幼兔心肌的保护作用。其机制与NAC提高缺血再灌注幼兔心肌的还原型巯基水平 ,增强心肌抗氧化损伤能力 。

Objective To evaluate the protective effects of St. Thomas cardioplegia supplemented with 4 mmol/L N acetyl L cysteine (NAC, NAC group) on the hypothermic ischemia reperfused immature hearts compared with those of St. Thomas cardioplegia (ST group). Methods The Langendorff Neeley isolated perfused working rabbit model was employed. Cardiac sarcoplasmic reticulums (SR) were isolated from the ischemia reperfusion myocardium. Then the content of total sulfhydryl (TSH), nonprotein sulfhydryl (NPSH), malmdialdehyde(MDA) and the activity of Ca 2+ ATPase were measured. Results ①The cardiac function during reperfusion was improved significantly in NAC group ( P <0.01). ②Compared with the ST group, the SR, TSH, NPSH contents remained in a higher level in the NAC group ( P <0.05), while the MDA content was lower in NAC group ( P <0.01). ③St. Thomas cardioplegia supplemented with NAC attenuated the inhibitive activity of the SR Ca 2+ ATPase during ischemia reperfusion ( P <0.01). Conclusion St. Thomas cardioplegia supplemented with NAC improves the myocardial protective effects on the ischemia reperfused immature myocardium. The mechanism might be that NAC can maintain the reduced thiol pool in the immature myocardium, enhance the anti oxidative capacity and attenuate the inhibition of SR Ca 2+ ATPase.