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目的:探讨慢性应激时大鼠中枢神经元损伤与大脑结构、功能改变之间的关系。方法:30只青年雄性Wistar大鼠,体重在185g~255g之间,随机分为对照组(C组,n=15)和实验组(T组,n=15)。T组大鼠单只分笼喂养,连续21天给予不可预见性综合刺激;C组大鼠分5只/笼喂养,不给予任何刺激。第22天脑组织取材、切片并进行TUNEL染色测定;实验前后分别进行旷场分析、体重测定和头部磁共振检查。结果:实验后的T组与C组相比:体重减轻(P<0.05);中央格停留时间延长(P<0.01);水平穿越格数减少(P<0.01);直立次数减少(P<0.01);修饰次数减少(P<0.01);粪便粒数增多(P<0.01)。在T组及C组海马各区均可以观察到细胞核内有棕黄色颗粒的凋亡细胞。慢性应激后T组与C组比较,凋亡细胞所占比例及凋亡细胞计数明显增加,两组有显著性差异(P<0.01)。无论与C组还是与实验前本组相比,实验后T组大鼠的侧脑室宽度显著增大,中脑导直径显著增大(P值均<0.01)。结论:慢性不可预见性综合应激明显增加了大鼠海马各亚区神经元凋亡的数量,并使其头部的MR图像表现为脑萎缩。
Objective: To investigate the relationship between the damage of central nervous system (CNS) and the changes of brain structure and function in rats with chronic stress. Methods: Thirty young male Wistar rats weighing 185g to 255g were randomly divided into control group (n = 15 in group C) and experimental group (n = 15 in group T). The rats in T group were fed only in cage and were given unpredictable comprehensive stimulation for 21 consecutive days. Rats in group C were fed with 5 rats / cage without any stimulation. Twenty-day brain tissue was taken, sectioned and TUNEL staining; open-field analysis before and after the experiment, body weight determination and head MRI. Results: Compared with group C, the weight of rats in group T was significantly lower than that in group C (P <0.05); the length of stay in central grid was prolonged (P <0.01) ); The number of modification decreased (P <0.01); the number of fecal particles increased (P <0.01). Apoptotic cells with brownish yellow granules in the nucleus could be observed in the hippocampus of T and C groups. Compared with group C, the proportion of apoptotic cells and the number of apoptotic cells in T group were significantly increased after chronic stress, with significant difference between the two groups (P <0.01). Compared with group C or before experiment, the width of lateral ventricle was significantly increased and the diameter of midbrain was significantly increased in experimental group (P <0.01). CONCLUSION: Chronic unpredictable stress can significantly increase the number of apoptotic neurons in hippocampal subfields of rats and make the MR images of the head show brain atrophy.