Suttorp N, Kästle S, Neuhof H
Department of Internal Medicine, Justus Liebig University of Giessen, FRG.
Lung. 1991;169(4):203-14. doi: 10.1007/BF02714155.
Exposure of cultured pulmonary artery endothelial cells to 95% O2 resulted in the following sequence of events: decrease in [3H]thymidine incorporation after 24 h; increase of intracellular glutathione (GSH) and loss of cellular protein after 48 h; increase of spontaneous and decrease of provoked prostacyclin formation as well as increased release of cellular LDH after 72 h. This oxygen toxicity model was used to study the following 2 questions. (1) What is the relative importance of the GSH redox cycle compared to catalase as antioxidative defense against hyperoxia? Endothelial cells were grown in selenium-depleted medium to inhibit glutathione peroxidase activity. Endothelial GSH biosynthesis was inhibited by buthionine sulfoximine. Catalase activity was reduced by aminotriazole. Endothelial cells with an impaired GSH redox cycle were easily killed by hyperoxia within 24 h, while inhibition of catalase did not enhance the susceptibility of endothelial cells to hyperoxia. (2) Can endothelial GSH content be increased by exogenous sulfhydryl reagents and does this result in an increase of endothelial cells' resistance to hyperoxia? Exogenous GSH, N-acetylcysteine, cysteine, and L-2-oxothiazolidine-4-carboxylate (L-2-oxo) increased intracellular GSH. All sulfhydryl reagents (with the exception of L-2-oxo) protected endothelial cells from hyperoxia. Concentrations of exogenous GSH and N-acetylcysteine that did not increase intracellular GSH reduced hyperoxia-induced endothelial cell injury. Thus the capacity of the GSH redox cycle rather than intracellular GSH levels or catalase determines endothelial cells' resistance to hyperoxia.
将培养的肺动脉内皮细胞暴露于95%氧气中会导致以下一系列事件：24小时后[3H]胸腺嘧啶核苷掺入减少；48小时后细胞内谷胱甘肽（GSH）增加且细胞蛋白丢失；72小时后自发性前列环素生成增加、诱发性前列环素生成减少以及细胞乳酸脱氢酶释放增加。该氧中毒模型用于研究以下两个问题。（1）与过氧化氢酶相比，GSH氧化还原循环作为对抗高氧的抗氧化防御机制，其相对重要性如何？内皮细胞在缺硒培养基中生长以抑制谷胱甘肽过氧化物酶活性。丁硫氨酸亚砜胺抑制内皮细胞GSH生物合成。氨基三唑降低过氧化氢酶活性。GSH氧化还原循环受损的内皮细胞在24小时内很容易被高氧杀死，而抑制过氧化氢酶并未增强内皮细胞对高氧的敏感性。（2）外源性巯基试剂能否增加内皮细胞GSH含量，这是否会导致内皮细胞对高氧的抗性增加？外源性GSH、N - 乙酰半胱氨酸、半胱氨酸和L - 2 - 氧代噻唑烷 - 4 - 羧酸（L - 2 - 氧代）增加细胞内GSH。所有巯基试剂（L - 2 - 氧代除外）都能保护内皮细胞免受高氧损伤。未增加细胞内GSH的外源性GSH和N - 乙酰半胱氨酸浓度可减轻高氧诱导的内皮细胞损伤。因此，GSH氧化还原循环的能力而非细胞内GSH水平或过氧化氢酶决定了内皮细胞对高氧的抗性。
