单一连续应激对大鼠行为学和海马Bcl-2、Bax表达的影响

目的 检测单一连续应激(single prolonged stress,SPS)对大鼠行为学和海马神经细胞Bax、Bcl-2表达的影响.方法 将Wistar大鼠分为对照组和应激组.应激组给予SPS应激,采用旷场实验、拒俘反应实验、Morries水迷宫实验等观察大鼠情感行为改变,采用化学发光法测定血清皮质醇浓度,应用免疫组织化学方法检测海马神经元Bcl-2、Bax的表达.结果 对照组水迷宫实验逃避潜伏期为5.632s±1.065s,应激组为20.762s±3.236s(t=9.932,P＜0.01)；对照组血清皮质醇浓度为1.25 μg/dl ±0.12μg/dl,应激组为0.58μg/dl±0.09μg/dl(t=7.340,P＜0.01).应激组海马Bcl-2、Bax表达升高,Bcl-2/Bax上调.结论 SPS应激能使大鼠表现出创伤后应激障碍行为,使海马神经细胞Bcl-2/Bax上凋,这可能与创伤后应激障碍发病机制有关.

Effect of single prolonged stress on behavior and expression of Bcl-2 and Bax in the rat hippocampus

Objective To observe the behavior change and the expression of Bcl-2 and Bax in the hippocampus of rats after treated with single-prolonged stress.Method Wistar rats were divided randomly into control group and stress group,and the stress rats were treated with single-prolonged stress.The behavior changes of rats were observed with open-field test,reject grip test and Morries water mace test.Hydrocortisone level in rats blood serum was determined with chemiluminescence.Immunohistochemistry was used to detect the expressions of Bax and Bal-2 in the hippocampal neurons.Results Morris water mace test showed that escape latency of control group was 5.632s±1.065s and stress group was 20.762s±3.236s(t=8.934,P<0.01).Hydrocortisone level of control group was 1.25μg/dl±0.12μg/dl and model was 0.58μg/dl±0.09μg/dl(t=8.075,P<0.01).The ratio of Bcl-2/Bax in control group was 0.904±0.109,while the stress group was 1.440±0.091(t=5.458,P<0.01).Conclusion The neuronal apoptosis in hippocampus may play a role in posttraumatic stress disorder.The increasing of Bcl-2 and Bax protein and the change of Bcl-2/Bax ratio may be the mechanism during single-prolonged stress.