创伤后应激障碍大鼠海马和杏仁核中神经元凋亡及Caspase-9的表达及其意义

目的:探讨创伤后应激障碍(PTSD)大鼠海马和杏仁核神经元凋亡及Caspase-9表达水平的变化,阐明PTSD大鼠海马与杏仁核体积异常的原因。方法:将100只雄性Wistar大鼠随机分为对照组(20只)和PTSD组(80只),利用改良的单一连续应激(SPS&S)制作PTSD大鼠模型。采用Morris水迷宫实验和僵立行为实验检测大鼠行为学表现;TUNEL方法检测大鼠海马和杏仁核神经元凋亡阳性细胞率;流式细胞术(FCM)检测大鼠海马和杏仁核神经元凋亡率;Western blotting法检测大鼠海马和杏仁核中Caspase-9表达水平。结果:PTSD组大鼠逃避潜伏期(EL)和僵立行为百分比显著高于对照组(P<0.05);PTSD后1、4、7和14d大鼠海马和杏仁核TUNEL阳性细胞和凋亡率高于对照组(P<0.05),28d与对照组比较差异无统计学意义(P>0.05);PTSD后1、4、7和14d大鼠海马和杏仁核Caspase-9表达水平高于对照组(P<0.05),28d与对照组比较差异无统计学意义(P>0.05)。结论:PTSD大鼠海马和杏仁核神经元凋亡增加,Caspase-9表达水平上调,提示其凋亡可能是引起海马与杏仁核体积异常的原因之一。

Neuronal apoptosis and expressions of Caspase-9 in hippocampus and amygdala of PTSD rats and their significances

Objective To observe the changes of neuronal apoptosis and expression levels of Caspase-9 in hippocampus and amygdala of posttraumatic stress disorder(PTSD) rats,and to disscus the mechanism of the volume abnormalities of hippocampus and amygdala.Methods 100 male Wistar rats were divided into control group(n=20) and PTSD group(n=80).The PTSD rat model was produced by giving the rats single-prolonged stress followed a single inescapable electric foot shock(SPS & S).The behavior changes of rats were examined using Morris water maze test and freezing behavior test.The positive apoptotic rates of cells and apoptotic rates in hippocampus and amygdala were detected by TUNEL-staining and flow cytometry(FCM).The expression level of Caspase-9 was detected by Western blotting method.Results The excape latency(EL) time and percentage of freezing behavior in PTSD group were higher than those in control group(P<0.05).The percentages of TUNEL-positive cells and the apoptotic rates in hippocampus and amygdala of PTSD 1,4,7 and 14 d rats were higher than those in control group(P<0.05),but there was no significant difference between PTSD 28 d rats and control rats(P>0.05).The expression levels of Caspase-9 in hippocampus and amygdala of PTSD 1,4,7 and 14 d rats were higher than those in control group(P<0.05).Conclusion The apoptosis of neurons and expression levels of Caspase-9 in hippocampus and amygdala of PTSD rats are increased,which indicates that apoptosis may be duced to the volume abnormalities of hippocampus and amygdala of PTSD.