Mechanisms of reoxygenation injury in cultured ventricular myocytes.
Mechanisms of reoxygenation injury in cultured ventricular myocytes.
复制标题
培养心室肌细胞复氧损伤的机制。
DOI：
10.1161/01.cir.83.2.566
复制
发表时间：
1991
期刊：
影响因子：
37.8
通讯作者：
Barry,WH
中科院分区：
文献类型：
--
作者：
Quaife,RA;Kohmoto,O;Barry,WH
为了探讨再灌注和复氧心肌损伤的相关因素，我们将培养的鸡心肌细胞暴露在20mM 2-脱氧葡萄糖、零葡萄糖和5 mM丙酮酸存在下的严重缺氧3h，然后将心肌细胞暴露在复氧中。乳酸脱氢酶(LDH)释放量在低氧3h时轻度升高，复氧时显著升高。同时检测缺氧和复氧过程中细胞内钙离子浓度([Ca~(2+)]i)和细胞运动的同步变化。低氧时，[Ca~(2+)]i升高到1微米以上，复氧后，[Ca~(2+)]_i突然略有下降，但仍高于1微米。低氧30分钟后，细胞出现稳定的僵硬。复氧在5分钟内引起明显的痉挛。用抑制钙依赖的力量发展的2，3-丁二酮单肟预处理心肌细胞，或用氰化物抑制复氧性过度收缩。在2，3-丁二酮单肟存在下，复氧后乳酸脱氢酶的释放也显著减少。缺氧时用超氧化物歧化酶和过氧化氢酶处理心肌细胞也能减少复氧时LDH的释放。我们的结论是，复氧过程中[Ca~(2+)]i的突然升高并不是复氧损伤的原因。然而，在[Ca~(2+)]i升高的情况下，复氧和由此导致的可能的ATP重新合成导致[Ca~(2+)]_i依赖的肌丝交叉桥循环，由此导致的过度收缩导致心肌细胞损伤。在这个系统中，复氧后产生的氧自由基似乎也会导致细胞损伤。
To investigate factors contributing to reperfusion and reoxygenation myocardial injury, we exposed layers of cultured chick ventricular myocytes to severe hypoxia for up to 3 hours in the presence of 20 mM 2-deoxyglucose, zero glucose, and 5 mM pyruvate, and then exposed the myocytes to reoxygenation. Lactate dehydrogenase (LDH) release was moderately increased during 3 hours of hypoxia but was increased markedly during reoxygenation. Coincident changes in intracellular calcium concentration ([Ca2+]i) and cell motion were also measured during hypoxia and reoxygenation. During hypoxia, [Ca2+]i increased to more than 1 microM, and with reoxygenation, [Ca2+]i abruptly decreased slightly but remained elevated more than 1 microM. Cells developed a stable rigor after 30 minutes of hypoxia. Reoxygenation caused a marked hypercontracture within 5 minutes. Pretreatment of myocytes with either 2,3-butanedione monoxime, which inhibits Ca2(+)-dependent force development, or cyanide inhibited reoxygenation hypercontracture. LDH release after reoxygenation was also significantly reduced in the presence of 2,3-butanedione monoxime. Treatment of myocytes with superoxide dismutase and catalase during hypoxia also resulted in a decrease in LDH release during reoxygenation. We conclude that an abrupt increase in [Ca2+]i during reoxygenation does not account for reoxygenation injury. However, in the presence of elevated [Ca2+]i, reoxygenation and the resulting probable resynthesis of ATP causes [Ca2+]i-dependent myofilament crossbridge cycling, and the resulting hypercontracture contributes to myocyte damage. The generation of oxygen free radicals after reoxygenation also appears to contribute to cell injury in this system.