RESPIRATORY ACTIVITY OF ISOLATED RAT-LIVER MITOCHONDRIA FOLLOWING INVITRO EXPOSURE TO OXYGEN SPECIES - A THRESHOLD STUDY
RESPIRATORY ACTIVITY OF ISOLATED RAT-LIVER MITOCHONDRIA FOLLOWING INVITRO EXPOSURE TO OXYGEN SPECIES - A THRESHOLD STUDY
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DOI：
10.1016/0047-6374(90)90075-q
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发表时间：
1990-02-15
影响因子：
5.3
通讯作者：
REMACLE, J
中科院分区：
文献类型：
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作者：
CORBISIER, P;RAES, M;REMACLE, J
用离体大鼠肝线粒体测定氧自由基暴露后的呼吸活性。我们的研究结果表明，线粒体呼吸是更敏感的O2。(-)而不是H2 O2。然而，亚铁离子由于产生羟基自由基而显著增强了产生H2 O2的酶系统的毒性。黄嘌呤/黄嘌呤氧化酶系统中的SOD和葡萄糖/葡萄糖氧化酶系统中的过氧化氢酶可提供对这些氧物种的保护。Fe ~（2+）与H_2O_2的结合对植物的伤害最大。在这种情况下，哦。是在类似芬顿的反应中形成的。事实上，OH。是最具破坏性的分子，这说明过氧化氢酶和去铁胺是该系统中的有效保护剂。氧气的阈值水平。(-)和H_2O_2能抑制线粒体呼吸。它的结论是，在正常的呼吸，这样的阈值在体内没有达到，线粒体呼吸活性的损害似乎并不起源于这些细胞器中的天然自由基的生产。然而，如果自由基的产生超过了防御能力，如在氧化应激下，则可以超过临界阈值，呼吸受损，导致不可逆的损害。
Respiratory activity of isolated rat liver mitochondria was assayed following in vitro exposure to oxygen radicals. Our results show that mitochondrial respiration is more sensitive to O2.(-) than to H2O2. However, ferrous ions drastically enhance the toxicity of the enzymatic system generating H2O2 because of the production of the hydroxyl radicals. A protection against those oxygen species could be given by SOD in the xanthine/xanthine oxidase system and by catalase with the glucose/glucose oxidase system. The most damaging system was the combination of Fe2+ with H2O2. In this case, OH. is formed in a Fenton-like reaction. The fact that the OH. is the most damaging molecule accounts for the finding that catalase and desferrioxamine were efficient protectors in this system. Threshold levels of O2.(-) and H2O2 able to inhibit the mitochondrial respiration have been estimated. It is concluded that under normal respiration such thresholds are not reached in vivo and that the impairment of the mitochondrial respiratory activity does not seem to originate only from the natural free radical production in those organelles. However, if the production of free radicals is such to exceed the defense capability, like under oxidative stress, then the critical threshold can be surpassed and the respiration impaired leading to irreversible damages.