慢性睡眠剥夺对大鼠学习记忆功能及海马、下丘脑多巴胺含量和D_1受体表达的影响

Effects of chronic sleep deprivation on learning and memory abilities,brain dopamine content and D_1 receptor expression in rats

目的研究慢性睡眠剥夺(CSD)对大鼠学习记忆功能的损害以及对海马、下丘脑中多巴胺(DA)含量和D1受体表达量的影响。方法健康成年雄性SD大鼠经过筛选后随机分为CSD组、大平台铁丝网格实验对照(TC)组和空白对照(BC)组,每组10只。采用改良多平台睡眠剥夺法建立大鼠CSD模型,每天剥夺18 h,连续21 d。TC组除剥夺箱底为罩有铁丝网格的大平台外,其他环境与CSD组一致。利用Morris水迷宫和自主活动箱在CSD的第7、14、21天检测大鼠学习记忆功能的变化;CSD 21 d后分别应用高效液相-电化学(HPLC-ECD)法和蛋白质印迹法检测大鼠海马、下丘脑中DA含量和D1受体蛋白表达量的变化。结果与BC组和TC组相比,CSD组大鼠毛色无光泽、精神疲惫且易激惹,自CSD 3 d起,体质量在各时间点降低,差异有统计学意义(P<0.01)。CSD组大鼠与其他两组相比,逃逸潜伏期在各时间点延长,穿环数减少,差异有统计学意义(P<0.01);与其他两组相比,CSD组大鼠自主活动总路程缩短(P<0.05)、自主活动次数减少(P<0.01);HPLC-ECD及蛋白质印迹结果显示,CSD组大鼠与其他两组相比,海马及下丘脑中DA含量、D1受体蛋白表达均减少,差异有统计学意义(P<0.05)。TC组与BC组大鼠相比,学习记忆能力、各脑区DA含量和D1受体蛋白表达差异均无统计学意义。结论CSD可损害大鼠学习记忆功能,海马、下丘脑中DA含量和D1受体表达水平降低可能是其潜在机制之一。

Objective To investigate the effects of chronic sleep deprivation （CSD） on the learning and memory abilities, brain dopamine（DA） content and D1 receptor expression in rat hippocampus and bypothalamus. Methods Healthy adult male Sprague-Dawley （SD） rats were randomly divided into CSD group, treatment control（TC） group and blank eontrol（BC） group after screening experiment. Each group included 10 rats. Rat CSD model was established by modified multiple platform method （MMPM）, in which the rats were subjected to 18 h/d sleep deprivation（PM16：00-AM10：00）for 21 days. Rats in TC group were given similar deprivation as CSD group, but lived in a deprivation box with bottom covered with wire grid. The learning and memory abilities of rats were measured by Morris water maze and open-field test at CSD 7, 14, and 21 d. DA content and D1 receptor protein expression in hippocampus and hypothalamus were determined by high performance liquid chromatography- electrochemical detector （HPLC-ECD） and Western blotting analysis, respectively. Results Compared with BC and TC groups, CSD rats were exhausted and irritated, without sleek hair. The weight of CSD rats were decreased significantly from the third day of sleep deprivation （P〈0.01）. The escape latency in Morris water maze of CSD group was increased significantly and the platform crossings decreased significantly compared with those of the other two groups （P〈0.01）. The spontaneous motor activity distance and activity times were also significantly decreased in CSD group （P〈0.05）. The hippocampus and hypothalamus DA content and D1 receptor protein expression were significantly decreased in CSD group as determined by HPLC- ECD and Western blotting analysis （P〈0. 05）. As expected, there were no significant differences in the above parameters between BC and TC group. Conclusion CSD can impair the learning and memory abilities in rats. Decreased dopamine and D1 receptor in hippocampus and hypothalamus may be involved in modulating the learning and memory dysfunction.