Induction of Thermotolerance in Chinese Hamster Ovary Cells by High (45°) or Low (40°) Hyperthermia
Induction of Thermotolerance in Chinese Hamster Ovary Cells by High (45°) or Low (40°) Hyperthermia
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发表时间：
1978-03
期刊：
影响因子：
11.2
通讯作者：
K. Henle;J. E. Karamuz;D. Leeper
中科院分区：
文献类型：
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作者：
K. Henle;J. E. Karamuz;D. Leeper
中国仓鼠卵巢（CHO）细胞经45°高温诱导的耐热性，在37°高温下发育后，其45°高温存活曲线的d0升高，但外推数n降低。耐热性发展的时间进程和程度取决于热疗治疗。在45°温度下暴露10分钟后的2小时内，随后的45°高温生存曲线的n增加了约5倍，而d0变化不大。此后，n恢复到控制值，而d0在8小时内增加了5倍，然后在37°孵育每小时45°时以0.1 min的速度缓慢消失。在45°条件下5分钟的调节剂量使随后的45°热存活曲线的d0在2小时内增加了3.3倍，但随后d0以与在45°条件下10分钟处理后相同的速率恢复到控制值。CHO细胞在40°条件下正常生长，超过2代没有细胞死亡的迹象，在45°条件下急性加热前，在40°条件下培养0至7小时，就d0的增加而言，没有诱导耐热性。然而，经过40°预孵育7小时，45°热存活曲线的dq增加了约3倍。在45°热处理期间，将孵育温度从37°提高到39-41°，并没有改变后续45°热存活曲线的耐热性d0，但将n降低到1.0。此外，45°条件和39°、40°和41°孵育后的存活曲线分别以5.3、47和360的倍数向下移位。45°c后39-41°c的高温孵育导致的细胞杀伤增强可能是由于亚致死损伤向致死损伤的转化而独立于热耐受性的诱导。
Abstract Thermotolerance induced in Chinese hamster ovary (CHO) cells by a 45° heat treatment and developed at 37° resulted in an increased D 0 but a reduced extrapolation number, n , of a subsequent 45° heat survival curve. The time course and magnitude of thermotolerance development were dependent upon the conditioning hyperthermia treatment. Within 2 hr after a 10-min exposure to 45°, the n of the subsequent 45° hyperthermia survival curve increased approximately 5-fold with little change in the D 0 . Thereafter, n returned to control values, whereas the D 0 increased by a factor of 5 by 8 hr and then only slowly disappeared at a rate of 0.1 min at 45° per hr of incubation at 37°. A conditioning dose of 5 min at 45° increased the D 0 of the subsequent 45° heat survival curve by a factor of 3.3 within 2 hr, but then the D 0 returned to control values at the same rate as after a conditioning treatment of 10 min at 45°. CHO cells incubated at 40° grew normally without any evidence of cell killing for more than 2 generations, and incubation at 40° for 0 to 7 hr prior to acute heating at 45° did not induce thermotolerance in terms of an increased D 0 . However, the D q of the 45° heat survival curve was increased approximately 3-fold by 40° preincubation for 7 hr. Increasing the incubation temperature from 37 to 39–41° between 45° heat treatments did not alter the thermotolerant D 0 of the subsequent 45° heat survival curve but did reduce n to 1.0. In addition, the survival curves following 45° conditioning and incubation at 39, 40, or 41° were displaced downward by factors of 5.3, 47, and 360, respectively. The enhanced cell killing resulting from post-45° hyperthermia incubation at 39–41° may be due to the conversion of sublethal damage to lethal damage independently of the induction of thermotolerance.