预缺氧对大鼠低压缺氧性脑损伤保护作用的实验研究

Protective effects of hypoxia preconditioning on rat brain against hypobaric hypoxia

目的探讨预缺氧对严重低压缺氧引起大鼠海马神经细胞损伤及学习记忆能力降低的保护作用。方法①Wistar大鼠分为对照组、单纯缺氧组、预缺氧复合缺氧组。光镜和电镜观察大鼠海马CA1区神经元形态变化;TUNEL法检测海马CA1区神经元凋亡。②单纯缺氧组和预缺氧复合缺氧组大鼠进行穿梭箱主动回避训练,随后进行低压缺氧,观察大鼠学习记忆能力的改变。结果预缺氧复合缺氧组大鼠CA1区神经元病理改变较轻,神经元凋亡显著低于单纯缺氧组(P<0.05);预缺氧复合缺氧组大鼠在严重缺氧后受电击次数和主动逃避时间的增加显著低于单纯缺氧组(P<0.05)。结论缺氧引起大鼠海马CA1区神经元凋亡等病理改变,并导致学习记忆能力降低;预缺氧对海马CA1区神经元的缺氧性损伤具有保护作用,并能有效减轻严重缺氧所导致的学习记忆能力下降。

Objective To explore the protective effects of hypoxia preconditioning on the injuries of hippocampal neurons and degression of memory ability caused by severe hypobaric hypoxia. Methods Wistar rats were divided randomly into control group （group C） , hypoxia group （group H, in hypobaric hypoxia chamber imitating l0 000 meters above sea level for 1 h/d, 3 d） and hypoxia preconditioning plus subsequent hypoxia group （ group HP, in hypobaric hypoxia chamber imitating 5 000 meters above sea level for 4 h/d, 7 d, then treated as group H）. The injuries and apoptosis of neurons in rat hippocampal CA1 were detected with HE staining, TUNEL and observed with electron microscopy. The changes of memory ability in group H and group HP after hypoxia were investigated with the active avoidance reaction. Results CA1 neuron injury in group HP was significantly slighter than group H, and apoptosis cells counting, electric shock times and mean time of active avoidance of rats in group HP were significantly lower than group H （P 〈 0.05 ）. Conclusion Severe hypoxia induced the neuron apoptosis in hippocampal CA1 and lesions of memory in rats, while hypoxia preconditioning can attenuate these injuries efficiently.