Spitz D R, Dewey W C, Li G C
J Cell Physiol. 1987 Jun;131(3):364-73. doi: 10.1002/jcp.1041310308.
Survival after H2O2 exposure or heat shock of asynchronous Chinese hamster ovary cells (HA-1) was assayed following pretreatment with mildly toxic doses of either H2O2 or hyperthermia. H2O2 cytotoxicity at 37 degrees C, expressed as a function of mM H2O2 was found to be dependent on cell density at the time of treatment. The density dependence reflected the ability of cells to reduce the effectiveness of H2O2 as a cytotoxic agent. When the survival data were plotted as a function of mumoles H2O2/cell at the beginning of the treatment, survival was independent of cell density. Cells pretreated with 0.1 mM (3-5 mumoles/cell X 10(-7)) H2O2 for 1 hr at 37 degrees C (30-50% survival) became resistant to a subsequent H2O2 treatment 16-36 hr after pretreatment [dose modifying factor (DMF) at 1% isosurvival = 4-6]. Their resistance to 43 degrees C heating, however, was only slightly increased over controls 16-36 hr following pretreatment (DMF at 1% isosurvival = 1.2). During this same interval, the synthesis of protein migrating in the 70 kD region of a one-dimensional SDS-polyacrylamide gel was enhanced twofold in the H2O2-pretreated cells. When the cells were heated for 15 min at 45 degrees C (40-60% survival), the survivors became extremely resistant to 43 degrees C heating and somewhat resistant to H2O2 (DMF at 1% isosurvival = 2). The heat-induced resistance to heat developed much more rapidly (reached a maximum between 6 and 13 hr) following pretreatment than the heat-induced resistance to H2O2 (16-36 hr). The enhanced synthesis of 70 kD protein after heat shock was greater in magnitude and occurred more rapidly following preheating than following H2O2 pretreatment. The cells that became resistant to H2O2 by either pretreatment (H2O2 or heat shock) also increased their ability to reduce the H2O2 cytotoxicity from the treatment medium beyond that of the untreated HA-1 cells. This may be one of the mechanisms involved in the increased resistance and a common adaptive mechanism induced by both stresses. These data indicate that mammalian cells develop resistance to H2O2 following mild pretreatment with H2O2 or heat shock. The cross-resistance induced by H2O2 and heat shock reinforce the hypothesis that some overlap in mechanisms exist between the cellular responses to these two stresses. However, the failure of H2O2 pretreatment to induce much resistance to heat indicates that there are also differences in the actions of the two agents.
在用轻度毒性剂量的过氧化氢（H₂O₂）或热疗进行预处理后，检测了异步生长的中国仓鼠卵巢细胞（HA - 1）在暴露于H₂O₂或热休克后的存活率。发现在37℃时，H₂O₂的细胞毒性（以毫摩尔H₂O₂表示）取决于处理时的细胞密度。密度依赖性反映了细胞降低H₂O₂作为细胞毒性剂有效性的能力。当将存活数据绘制为处理开始时每细胞微摩尔H₂O₂的函数时，存活与细胞密度无关。在37℃下用0.1 mM（3 - 5微摩尔/细胞×10⁻⁷）H₂O₂预处理1小时（存活率为30 - 50%）的细胞，在预处理后16 - 36小时对随后的H₂O₂处理产生抗性[1%等存活率时的剂量修正因子（DMF）= 4 - 6]。然而，在预处理后16 - 36小时，它们对43℃加热的抗性仅比对照略有增加（1%等存活率时的DMF = 1.2）。在同一时间段内，在一维SDS - 聚丙烯酰胺凝胶70 kD区域迁移的蛋白质合成在H₂O₂预处理的细胞中增强了两倍。当细胞在45℃加热15分钟（存活率为40 - 60%）时，存活细胞对43℃加热变得极具抗性，对H₂O₂也有一定抗性（1%等存活率时的DMF = 2）。热诱导的对热的抗性在预处理后比热诱导的对H₂O₂的抗性（16 - 36小时）发展得更快（在6至13小时之间达到最大值）。热休克后70 kD蛋白质合成的增强幅度更大，并且在预热后比在H₂O₂预处理后发生得更快。通过任何一种预处理（H₂O₂或热休克）对H₂O₂产生抗性的细胞，其从处理培养基中降低H₂O₂细胞毒性的能力也比未处理的HA - 1细胞有所增强。这可能是抗性增加所涉及的机制之一，也是两种应激诱导的共同适应性机制。这些数据表明，哺乳动物细胞在用H₂O₂或热休克进行轻度预处理后会对H₂O₂产生抗性。H₂O₂和热休克诱导的交叉抗性强化了这样一种假设，即细胞对这两种应激的反应机制存在一些重叠。然而，H₂O₂预处理未能诱导对热的大量抗性，这表明这两种试剂的作用也存在差异。
