THE MECHANISM OF PH-DEPENDENT HYDROGEN-PEROXIDE CYTO-TOXICITY INVITRO
THE MECHANISM OF PH-DEPENDENT HYDROGEN-PEROXIDE CYTO-TOXICITY INVITRO
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DOI：
10.1016/0003-9861(88)90139-7
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发表时间：
1988-09-01
影响因子：
3.9
通讯作者：
LINK, EM
中科院分区：
文献类型：
--
作者：
LINK, EM
本文研究了氢离子浓度和培养基组成对体外过氧化氢诱导上皮细胞克隆存活的影响。在pH 6.5的磷酸盐缓冲盐水中与H2O2孵育的细胞存活率为1.1倍。10-2，突然增加到9倍。10-2在pH 7.0。当细胞暴露于H2O2时，用Eagle’s minimum essential medium （SFMEM）杀菌效果的pH依赖性尤为明显：细胞存活率呈指数型依赖于pH值，变化幅度为1。10-1到9倍。pH值为6.5和7.5时，分别为10-1，并叠加了9.9倍的尖峰值。10-1 pH 7.0。H2O2细胞毒性在SFMEM中增强的pH依赖性被发现是由于该培养基中存在葡萄糖和组氨酸的添加作用。葡萄糖对细胞的保护作用随着氢离子浓度的增加而降低。组氨酸在ph依赖性存活谱中占中间最大值。此外，细胞存活的变化伴随着暴露细胞中GSSG的ph依赖性释放。培养基中的葡萄糖抑制GSSG外排。葡萄糖对细胞存活模式和相关GSSG释放的影响表明，戊糖磷酸途径支持的谷胱甘肽过氧化物酶活性在细胞保护中对细胞外H2O2毒性至关重要。
The present paper is concerned with the influence of hydrogen ion concentration and composition of the medium on clonogenic survival of epithelial cells exposed to hydrogen peroxide in vitro. The survival of cells incubated with H2O2 in phosphate-buffered saline at pH 6.5 was 1 .times. 10-2 and increased abruptly to 9 .times. 10-2 at pH 7.0. The pH dependence of the cytocidal effect was particularly conspicuous when Eagle''s minimum essential medium (SFMEM) was used for cell exposure to H2O2: the survival was characterized by exponential pH dependence and varied from 1 .times. 10-1 to 9 .times. 10-1 for pH 6.5 and 7.5, respectively, with a superimposed sharp peak value of 9 .times. 10-1 at pH 7.0. The enhanced pH dependence of the H2O2 cytotoxicity in SFMEM was found to result from the additive action of glucose and histidine present in this medium. Glucose alone protected the cells with the efficiency decreasing with increasing hydrogen ion concentration. Histidine was responsible for the intermediate maximum in the pH-dependent survival spectrum. In addition, the changes in cell survival were accompanied by pH-dependent release of GSSG from the exposed cells. The GSSG efflux was inhibited by glucose in the medium. The influence of glucose on both the pattern of cell survival and the associated GSSG release indicate that the glutathione peroxidase activity supported by the pentose phosphate pathway is crucial in cell protection against extracellular H2O2 toxicity.