生理学报Acta Physiologica Sinica, June 25 2003 55(3)

研究论文

活性氧和线粒体ATP敏感钾通道介导肿瘤坏死因子α对缺氧/复氧心肌的保护作用

傅琛, 曹春梅, 夏强*, 杨俊, 陆源

浙江大学医学院生理学教研室, 浙江杭州 310031

摘要: 在培养的乳鼠心肌细胞上, 研究肿瘤坏死因子α (TNF-α)对缺氧/复氧损伤心肌的保护作用的机制。结果发现: (1) 用TNF-α (10－500 U/ml)预处理, 缺氧/复氧后心肌细胞内锰超氧化物歧化酶(Mn-SOD)活性增高、乳酸脱氢酶(LDH)释放量减少(P<0.05); (2) 用抗氧化剂N-乙酰半胱氨酸 (NAC, 1 mmol/L)、抗霉素A (antimycin A, 50 μmol/L)、2-巯基丙酰氨基乙酸(2-MPG, 400 μmol/L)和铜/锌超氧化物歧化酸(Cu/Zn-SOD)抑制剂二乙基二硫代氨基甲酸盐(DDC, 100 nmol/L)预处理, 可取消TNF-α的抑制缺氧/复氧心肌细胞LDH释放和诱导Mn-SOD活性增高的作用; (3) mitoKATP通道抑制剂5-羟基酸(5-HD)预处理可阻断TNF-α对缺氧/复氧心肌细胞的保护作用; 选择性mitoKATP通道开放剂diazoxide (50 μmol/L)预处理可减少复氧后心肌细胞LDH的释放(P<0.01), 其作用可被5-HD (100 μmol/L)和NAC所抑制。上述结果表明, 活性氧和线粒体ATP敏感钾通道参与介导TNF-α对缺氧/复氧损伤的心肌保护作用。

关键词: 心肌细胞; 肿瘤坏死因子α (TNF-α); 缺氧; 复氧; 活性氧; 线粒体ATP敏感钾通道

中图分类号: Q463

Reactive oxygen species and mitochondrial KATP-sensitive channels mediated cardioprotection induced by TNF-α during hypoxia and reoxygenation

FU Chen, CAO Chun-Mei, XIA Qiang*, YANG Jun, LU Yuan

Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310031, China

Abstract:The aim of the present study was to testify whether the reactive oxygen species and mitochondrial ATP-sensitive potassium (KATP) channels were involved in the cardioprotection induced by tumor necrosis factor ( (TNF-α) in the cultured neonatal ventricular myocytes suffered from 12 h of hypoxia and 6 h of reoxygenation. We tested the release of lactate dihydrogenase (LDH) and manganese superoxide dismutase (Mn-SOD) with spectrophotometry. It was shown that pretreatment with TNF-α (10, 50, 100, or 500 U/ml) significantly increased the Mn-SOD activity and reduced LDH release in the neonatal ventricular myocytes subjected to hypoxia and reoxygenation. Pretreatment with NAC (1 mmol/L), antimycin A (50 μmol/L), 2-MPG (400 μmol/L), DDC (100 nmol/L) or 5-HD (100 μmol/L), respectively, attenuated the increase of Mn-SOD activity and reduction of LDH level induced by TNF-α in ventricular myocytes. Diazoxide (50 μmol/L), a selective opener of the mitochondrial KATP channel, decreased the LDH release of the myocytes subjected to hypoxia and reoxygenation, which could be abolished by pretreatment with NAC (1 mmol/L) or 5-HD (100 μmol/L). These results suggest that oxygen radicals signals and mitochondrial KATP channels involved in the cardioprotection induced by TNF-α.

Key words: myocytes; tumor necrosis factor α (TNF-α); hypoxia/reoxygenation; reactive oxygen species; mitochondrial ATP-sensitive potassium channels