急性重复缺氧对小鼠缺氧耐受性的影响及其机制的初步探讨

Effects of repeated exposure to hypoxia on hypoxia tolerance in mice

小鼠在密闭缺氧的重复作用下,对缺氧的耐受性逐次递增,第2、3、4、5次的耐受时间分别较第1次增加1.8、2.5、3.0和3.6倍;第4次重复缺氧后的动物在更低氧分压下的存活时间较正常对照动物延长10倍;其氰化钾中毒致死时间较正常动物推迟4倍。腹腔注入缺氧耐受小鼠脑匀浆提取液,可显著延长小鼠在低氧分压下的存活时间,与腹腔注入等体积生理盐水和注入等体积正常小鼠脑匀浆提取液组相比较,分别延长1.8和2.1倍。结果提示,急性重复缺氧,可能使组织细胞,特别是脑细胞发生某种可塑的或适应的变化,从而导致动物对缺氧具有非常高的耐受水平;急性重复缺氧小鼠脑中的一种或多种可提取并可通过血脑屏障的水溶性物质可能为该适应变化的一部分。

The hypoxia tolerance of mice was significantly increased by repetitive action of auto-hypoxia. The tolerance duration of the 2nd, 3rd, 4th and 5th run was 1.8 2.5 3.0 and 3.6 times longer than that of the Ist one. The survival time of mice that had been exposed to hypoxia repeatedly for four runs was 10 times longer than that of the control animals when both of them were placed in the same low pressure chamber and was 4 times longer while KCN was administrated. The survival time under low oxygen pressure in mice injected with brain extract of resistant mice was 1.8 and 2.1 times longer than that of the saline-injected or normal mice's brain extract-injected animals respectively. These results indicate that some plastic or adaptic changes might occur in the tissue cells particularly in the brain cells during acute and repeated hypoxia. They lead the animals' hypoxia tolerance to a very high level. Water soluble antihypoxic or hypoxia-resistant elements might exist in the brain of hypoxia resistant animals, which were extractable, transferable, and permeable to the blood brain barrier.