Antioxidants protect rat diaphragmatic muscle function under hypoxic conditions
Antioxidants protect rat diaphragmatic muscle function under hypoxic conditions
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DOI：
10.1152/jappl.1998.84.6.1960
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发表时间：
1998-06-01
影响因子：
3.3
通讯作者：
Clanton, TL
中科院分区：
文献类型：
--
作者：
Mohanraj, P;Merola, AJ;Clanton, TL
在缺氧时，线粒体呼吸减少，从而导致还原当量的积累，这些还原当量不能在细胞色素氧化酶处转移到O-2。这种情况，称为还原应激，可以矛盾地导致反应性O-2物质的形成增强，或细胞防御氧化应激的能力降低。我们假设抗氧化剂可以在缺氧条件下保护组织。将大鼠膈肌条在含有四种抗氧化剂之一的组织浴中孵育：N-乙酰-L-半胱氨酸、二甲基亚砜、超氧化物歧化酶或Tiron。在电场中直接刺激条。研究了基线氧合（95%O-2- 5%CO2），缺氧30分钟后（95%N-2- 5%CO2），和复氧后30分钟的力-频率关系。在所有组织中，抗氧化剂显著减轻缺氧时收缩功能的丧失（P < 0.01），并显著促进复氧时的恢复（P < 0.05）。我们的结论是，细胞内和细胞外的抗氧化剂改善骨骼肌的收缩功能，在缺氧和促进恢复过程中，在体外系统的复氧。抗氧化剂在低氧暴露期间的强烈影响表明，它们在还原环境中保护细胞功能的效果与在氧化环境中一样。
In hypoxia, mitochondrial respiration is decreased, thereby leading to a buildup of reducing equivalents that cannot be transferred to O-2 at the cytochrome oxidase. This condition, called reductive stress, can paradoxically lead to enhanced formation of reactive O-2 species, or a decrease in the ability of the cell to defend against an oxidative stress. We hypothesized that antioxidants would protect tissues under conditions of hypoxia. Rat diaphragm strips were incubated in tissue baths containing one of four antioxidants: N-acetyl-L-cysteine, dimethyl sulfoxide, superoxide dismutase, or Tiron. The strips were directly stimulated in an electrical field. Force-frequency relationships were studied under baseline oxygenation (95% O-2-5% CO2), after 30 min of hypoxia (95% N-2-5% CO2), and 30 min after reoxygenation. In all tissues, antioxidants markedly attenuated the loss of contractile function during hypoxia (P < 0.01) and also significantly improved recovery on reoxygenation (P < 0.05). We conclude that both intracellular and extracellular antioxidants improve skeletal muscle contractile function in hypoxia and facilitate recovery during reoxygenation in an in vitro system. The strong influence of antioxidants during hypoxic exposure suggests that they can be as effective in protecting cell function in a reducing environment as they have been in oxidizing environments.