低氧预处理重塑海马兴奋/抑制平衡促进神经细胞生存

Hypoxic preconditioning facilitating the survival of neurons in hippocampus

目的观察急性低氧和重复低氧预处理对小鼠海马组织兴奋性与抑制性氨基酸含量的影响,同时观察海马组织尼氏染色,初步探讨低氧预处理保护神经组织的机制。方法小鼠随机分为对照组、急性低氧组及低氧预处理组,3组动物分别进行海马组织氨基酸神经递质检测和尼氏染色。结果急性低氧可显著增加海马组织天门冬氨酸的含量,并降低抑制性氨基酸甘氨酸的含量,兴奋与抑制氨基酸递质失衡。重复低氧预处理并不增加海马组织天门冬氨酸的含量,但甘氨酸含量显著增加,天门冬氨酸与甘氨酸含量之比逆转。尼氏染色显示急性低氧组与重复低氧预处理组海马组织变性细胞数目无显著差异,均显著高于对照组。但急性低氧组神经细胞内尼氏体数量明显减少。结论重复低氧预处理可通过重塑低氧组织的兴奋与抑制平衡,使低氧组织处于相对的稳态,改善神经细胞的生存环境。

Objective To observe the effect of acute hypoxia and repetitive hypoxic precondi- tioning on the survival of hippocampus neurons. The contents of excitatory amino acid neuro- transmitter and inhibitory amino acid neurotransmitter in hippocampus were detected, and the morphological characteristics of neurons were also observed after Nissl staining. The underly- ing mechanism was fundamentally explored. Methods Adult ICR mice were randomly divided into the control, ~cute hypoxic, and repetitive hypoxic preconditioned groups. The biochemistry techniques of high performance liquid chromatography were applied to determine the contents of excitatory and inhibitory amino acid neurotransmitter in the hippocampus of mice after hy- poxic treatment. Nissl staining was carried out on the 5th day after hypoxic treatment. Results The content of excitatory amino acid in hippocampus was significantly increased after acute hy- poxia, implying disequilibrium between excitation and inhibition in hippocampus. In the hypoxic preconditioned mice, the content of excitatory amino acid in hippocampus was not increasedsignificantly, but the content of glycine was significantly increased. Nissl staining displayed co- ordinate neuronal death in hippocampus CA1 region in both acute hypoxie group and repetitive hypoxic preconditioned group 5 d after hypoxic treatment. The numbers of degenerating neurons in these two groups were significantly higher than those of the control group, but the number of Nissl body was significantly decreased in acute hypoxic group than that of repetitive hypoxie preconditioned group. Conclusion Repetitive hypoxic preconditioning may protect brain tissue under hypoxic condition through remodeling the balance between excitation and inhibition in hippocampus.