Fenton L H, Robinson M B
Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania 19104.
Brain Res. 1993 Dec 31;632(1-2):143-9. doi: 10.1016/0006-8993(93)91149-m.
Repeated exposure to increased partial pressure of oxygen (PO2) is the standard of care for several medical conditions. The side-effects of repeated exposure to hyperbaric oxygen (HBO), however, are not well defined. Previous studies have demonstrated that acute exposure of rats to HBO causes hypothermia that precedes convulsions. In the present studies, rats that were repeatedly exposed to 100% oxygen at 4 atmospheres absolute (ATA) pressure developed convulsions earlier than naive controls. There was also a trend toward less hypothermia in the rats repeatedly exposed to oxygen. The purpose of this study was to test the hypothesis that repeated exposure to HBO increases sensitivity to convulsions induced by HBO and to determine if the time to onset of convulsions is affected by the hypothermia caused by exposure to HBO. Rats were repeatedly exposed to 2 ATA oxygen for a total of 10 days. After 72 h, these rats were challenged by exposure to 100% oxygen at 4 ATA pressure. Rats repeatedly exposed to HBO had convulsions significantly earlier than the naive controls (84 +/- 8 min compared to 147 +/- 11 min), and they developed significantly less hypothermia. Control studies suggested that the decrease in the degree of hypothermia was caused by both repeated exposure to oxygen and adaptation to the mild restraint used during oxygen re-exposures. Adaptation to restraint eliminated the hypothermia induced by oxygen but did not change the time to onset of convulsions. Increased sensitivity to convulsions was present after five exposures to 2 ATA oxygen and persisted for 10 days after the last 2 ATA oxygen re-exposure.(ABSTRACT TRUNCATED AT 250 WORDS)
反复暴露于升高的氧分压（PO2）是多种医疗状况的标准治疗方法。然而，反复暴露于高压氧（HBO）的副作用尚未明确界定。先前的研究表明，大鼠急性暴露于HBO会导致体温过低，随后出现惊厥。在本研究中，反复暴露于4个绝对大气压（ATA）的100%氧气中的大鼠比未处理的对照组更早出现惊厥。反复暴露于氧气的大鼠体温过低的情况也有减轻的趋势。本研究的目的是检验以下假设：反复暴露于HBO会增加对HBO诱导惊厥的敏感性，并确定惊厥发作时间是否受HBO暴露引起的体温过低影响。大鼠反复暴露于2 ATA氧气中，共10天。72小时后，这些大鼠接受4 ATA压力下100%氧气的激发试验。反复暴露于HBO的大鼠惊厥发作明显早于未处理的对照组（分别为84±8分钟和147±11分钟），且体温过低的程度明显减轻。对照研究表明，体温过低程度的降低是由反复暴露于氧气以及对再次暴露于氧气期间使用的轻度束缚的适应所致。对束缚的适应消除了氧气诱导的体温过低，但并未改变惊厥发作时间。在五次暴露于2 ATA氧气后，对惊厥的敏感性增加，并在最后一次2 ATA氧气再暴露后持续10天。（摘要截断于250字）
