慢性应激对大鼠海马齿状回神经发生的影响

The impact of chronic stress on neurogenesis in hippocampal dentate gyrus in rats

目的:探讨慢性应激对大鼠海马齿状回(DG)新生神经细胞增殖及成熟的影响。方法:用慢性束缚法制作大鼠慢性应激模型,利用Morris水迷宫试验对其进行空间学习记忆功能的评价,并通过免疫荧光染色及共聚焦显微镜成像技术观察慢性应激后海马DG区DCX阳性细胞的数量及树突长度的变化。结果:模型组大鼠在水迷宫实验中的逃避潜伏期为(48.13±4.7)s,明显长于对照组的(13.64±3.55)s;模型组大鼠在限定时间内穿越平台的次数为(1.33±0.09)次,明显少于对照组的(2.75±0.16)次,差异均有统计学意义(均P<0.05)。模型组大鼠海马DG区每张切片的DCX阳性细胞数量为(19.35±5.6)个,较对照组的(37.89±9.4)个明显减少;模型组大鼠海马DG区DCX阳性细胞树突总长度为(168.44±9.46)μm,较对照组的(235.67±19.57)μm明显缩短,差异均有统计学意义(均P<0.05)结论:慢性应激会抑制大鼠新生神经细胞的增殖及成熟,并可能影响大鼠的学习记忆功能。

Objective：To investigate the impact of chronic stress on proliferation and maturation of newborn nerve ceils in hippocampal dentate gyrus in rats. Methods：The chronic stress rat models were established by chronic bondage method and evaluated their spatial learning and memory abilities by the Morris water maze. Furthermore,immunofluorescence staining and confocal microscopy were used to observe the changes of DCX- positive cell number and the length of dendrites in the DC region of dentate gyrus after chronic stress. Results： The escape latency in model group （48. 13 ± 4.7） second was significantly longer than that in control group （13.64 ± 3.55 ）second. The number of platform crossing was significantly less in model group （1.33 ± 0. 09） than in the control group （2.75 ±0.16） （both P 〈0.05）. Compared with control group （37.89 ±9.4） ,model group （37.89 ± 9.4） had significantly decreased DCX positive cell number in DC region in hippocampal denate gyms. The total length of dendrites of DCX positive cells in DC region in hippocampal denate gyrus was significantly shorter in model group （168.44 ± 9.46）μm than in control group （235.67 ± 19.57）μm （both P 〈 0.05 ）. Conclusion： Chronic stress could inhibit the proliferation and maturation of newborn nerve cells in rats, which might affect the learning and memory abilities of rats.