体育锻炼通过调节自噬改善睡眠剥夺所致的认知功能障碍

Physical exercise ameliorates cognitive impairment caused by sleep deprivation by modulating autophagy

摘要

目的 自噬失调导致的神经元坏死是睡眠障碍引发认知功能降低的关键机制，体育锻炼是改善认知功能的有效方法，但相关机制尚有待研究。本研究旨在探讨体育锻炼对睡眠障碍相关自噬异常的调节作用。 方法 选用C57BL/6雄性小鼠，采用睡眠剥夺模拟睡眠障碍，小鼠随机分为空白对照（control，CON）组、运动对照（exercise，EX）组、睡眠剥夺（sleep deprivation，SD）组及运动干预（EX+SD）组。采用Morris水迷宫评价小鼠认知功能，HE染色及透射电镜评估海马神经元损伤程度，蛋白免疫印迹法检测自噬蛋白的表达。 结果 与空白对照组相比，睡眠剥夺显著延长小鼠寻找隐藏平台的时间（P=0.000）、减少小鼠在目标象限停留的时间（P=0.000）；形态学分析发现，睡眠剥夺小鼠海马CA3区神经元发生变性、出现细胞核固缩（P=0.000），而神经元超微结构中自噬体增加（P=0.000）；蛋白免疫印迹发现，睡眠剥夺小鼠海马中Beclin-1（P=0.000）、微管相关蛋白1轻链3-Ⅱ型（microtubule-associated protein light chain 3 Ⅱ，LC3 Ⅱ）（P=0.000）和p62（P=0.000）的水平均显著升高。而体育锻炼可抑制睡眠剥夺诱导的Beclin-1（P=0.01）、LC3Ⅱ（P=0.018）和p62（P=0.036）上调，减少神经元中的自噬体数目（P=0.001），减轻神经元形态学损伤（P=0.002），改善实验小鼠认知行为学异常。 结论 本研究的结果表明，睡眠剥夺可诱发自噬启动，但自噬通量受阻，这可能是导致神经元损伤和认知障碍的重要病理环节，而运动锻炼可促进自噬流通畅、减轻神经元损伤和认知障碍。

Abstract

Objective Neuronal necrosis resulting from autophagy dysregulation is a key mechanism of cognitive decline caused by sleep disorders. Physical exercise is an effective method to improve cognitive function，but the related mechanism remains to be investigated. The objective of this study was to explore the regulatory effect of physical exercise on autophagy abnormalities associated with sleep disorders. Methods C57BL/6 male mice were randomly divided into a control group，an exercise（EX） group，a sleep deprivation （SD） group，and an exercise intervention（EX+SD） group. Sleep deprivation was used to simulate sleep disorders. Morris water maze was used to evaluate the cognitive function of mice. Hematoxylin-eosin staining and transmission electron microscopy were used to evaluate the degree of hippocampal neuronal injury. Western blotting was adopted to measure the expression of autophagy-related proteins. Results Compared with the control group，sleep deprivation significantly extended the time of searching for the hidden platform （P=0.000） and reduced the time of staying in the target quadrant（P=0.000）. The morphological analysis revealed that neurons in CA3 region of the hippocampus of sleep-deprived mice showed degeneration and karyopyknosis（P=0.000），while autophagosomes increased in the neuron ultrastructure （P=0.000）. Western blotting showed that Beclin-1（P=0.000），LC3（microtubule-associated protein light chain 3，MAPLC3）Ⅱ（P=0.000），and p62（P=0.000） levels were significantly increased in the hippocampus of sleep-deprived mice. However，physical exercise inhibited the up-regulation of Beclin-1（P=0.01），LC3Ⅱ（P=0.018），and p62（P=0.036） induced by sleep deprivation，reduced the number of autophagosomes in neurons（P=0.001），alleviated the morphological injury of neurons（P=0.002），and improved the cognitive behavioral abnormalities of experimental mice. Conclusion The results of this study indicate that sleep deprivation can induce autophagy initiation，but the autophagy flux is blocked，which may be an important pathological link leading to neuronal injury and cognitive impairment. Exercise can promote the patency of autophagy flux and reduce neuronal injury and cognitive impairment.

关键词

睡眠障碍 / 睡眠剥夺 / 体育锻炼 / 认知功能 / 自噬

Key words

sleep disorder / sleep deprivation / physical exercise / cognitive function / autophagy