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目的 通过观察急性缺氧适应时脑组织一氧化氮 ( NO)和内皮素 ( ET)的变化 ,探讨缺氧适应影响脑缺血缺氧损伤的机制。方法 应用急性重复缺氧模型 ,观察并测定 4次缺氧后及应用NO底物 L -精氨酸、一氧化氮合酶抑制剂 ( L - NAME)后脑组织 NO、ET含量和低氧存活时间及缺氧适应对缺血缺氧脑组织 NO、ET及脑含水量影响。结果 ( 1)缺氧适应明显延长小鼠在低氧存活时间 ,且 NO明显增加 ,L - NAME抑制这一改变 ,ET变化不明显 ;( 2 )缺氧适应抑制缺血缺氧脑 ET的增加和脑含水量的增加 ,辅用 L -精氨酸抑制作用更明显 ,而辅用 L - NAME作用相反。结论 缺氧适应增加严重低氧的耐受性 ,NO参与缺氧适应机制 ,能抑制缺氧缺血脑组织 ET的增加 ,缺氧适应可能通过此机制对缺氧缺血脑损伤起保护作用。
Objective To observe the changes of brain tissue nitric oxide (NO) and endothelin (ET) during acute hypoxia adaptation and to explore the mechanism of hypoxia adaptation affecting cerebral ischemia and hypoxia injury. Methods The model of acute repeated hypoxia was used to observe the content of NO and ET and the survival time of hypoxia after 4 times of hypoxia and NO substrate L - arginine and nitric oxide synthase inhibitor (L - NAME) And Hypoxia Adaptation on NO, ET and Brain Water Content in Hypoxic-Ischemic Brain. Results (1) Hypoxia adaptation prolonged the survival time of hypoxia mice, and NO increased obviously. L - NAME inhibited this change, and ET did not change obviously. (2) Hypoxia adaptation inhibited the increase of ET And brain water content increase, supplemented with L - arginine inhibition is more obvious, while supplemented with L - NAME opposite effect. Conclusions Hypoxia adaptation can increase the tolerance of severe hypoxia. NO participates in hypoxia adaptation mechanism and inhibits the increase of ET in hypoxic-ischemic brain tissue. Hypoxia adaptation may play a protective role in hypoxic-ischemic brain damage by this mechanism.