皮质酮与应激在大鼠PTSD样记忆损害形成过程中的交互作用

目的 研究皮质酮与应激在大鼠的创伤后应激障碍（PTSD）样记忆损害中的作用及交互效应.方法 分别以0 mA、0.8 mA及1.4 mA的电击量对大鼠进行预实验.首先大鼠接受恐惧任务训练,训练后24 h进行场景恐惧记忆测试,然后采用泛化测试验证大鼠PTSD样记忆损害模型是否复制成功.为了观察糖皮质激素的作用,采用双侧肾上腺切除术,并以皮质酮替代饲养,大鼠在手术后7天进行行为学实验.根据是否接受皮质酮替代及电击量分为四组：空白对照组（无皮质酮替代,电击量0 mA）、皮质酮组（皮质酮替代,电击量0 mA）、电击组（无皮质酮替代,电击量1.4 mA）、皮质酮-电击组（皮质酮替代,电击量1.4 mA）.采用析因设计资料的方差分析,对皮质酮与电击的交互作用进行统计分析.结果 0.8 mA组与0 mA组比较,大鼠的僵住反应百分比升高;0.8 mA组与1.4 mA组比较,大鼠的僵住反应百分比下降,并且1.4 mA组出现泛化效应.在析因设计资料的方差分析中,皮质酮-电击组与其他各组的僵住反应百分比均差异有统计学意义（P＜0.05）,其他各组之间差异无统计学意义.皮质酮（F=6.464,P＜0.05）和电击（F=53.419,P＜0.01）均对PTSD样记忆损害形成发挥作用,且皮质酮与电击之间存在交互效应（F=11.580,P＜0.05）.结论 高电击量（1.4 mA）能够诱导出大鼠PTSD样记忆损害,皮质酮与应激在此过程中存在交互效应.

Interactional effects of corticosterone and stress in the formation of PTSD-like memory impairment rats

Objective To investigate the interactional roles corticosterone and stress played during the PTSD-Like memory impairment.Methods First we established the model of PTSD-like memory using three levels of electric shock：0 mA,0.8 mA and 1.4 mA.The freezing time percent of each group were calculated 24 hours later in order to find which group of rats obtained the PTSD-like memory,and generalizing tests was used to verify it.After the model was established,rats received adrenalectomy （ADX） were operated bilaterally in order to investigate the effect of corticosterone and fed with corticosterone in the drinking water 7 days before fear conditioning.These rats were divided into four groups：control group （no corticosterone supplement,0 mA shock）,Cort group （corticosterone supplement,0 mA shock）,shock group （no corticosterone supplement,1.4 mA shock）,Cort-shock group （corticosterone supplement,1.4 mA shock）.A two-way factorial analysis of variance was used to determine whether there was a significant interaction between corticosterone and shock.Results The freezing time percent of group 0.8 mA raised compared with the group 0 mA,whereas the freezing time percent of group 1.4 mA showed reversely and the generalizing effects appeared,compared with group 0.8 mA.In two-way factorial analysis design,the freezing time percent of Cort-shock group significantly increased （P〈0.05） compared with other groups,and there was no significant variance among the other groups.Corticosterone （F=6.464,P〈0.05） and stress （F=53.419,P 〈0.01） played parts in the formation of PTSD-like memory impairment,and they interacted with each other （F=11.580,P〈0.05）.Conclusion PTSD-like memory impairment can be induced on rats with high （1.4 mA） electrical shock,and they have interactional effect with each other in the process.