比较轻柔刺激与剥夺杆睡眠剥夺模型对雌性小鼠情景恐惧记忆的影响

Comparing the effects of gentle handling and rotating bar sleep deprivation methods on episodic fear memory in female mice

目的探讨轻柔刺激和剥夺杆睡眠剥夺方法对雌性小鼠的情景恐惧记忆的影响。方法15只C57BL/6J雌性小鼠随机分为对照组、轻柔刺激剥夺组、剥夺杆剥夺组,每组各5只。其中,轻柔刺激剥夺组使用轻柔刺激法进行建模;而剥夺杆剥夺组则采用Pinnacle自动睡眠剥夺系统进行建模;对照组小鼠留在原饲养笼中。建模时间为早8点至晚17点,共9 h,在此期间小鼠能自由获取食物和水。在睡眠剥夺的前1 d,将小鼠放入四站式条件恐惧系统的训练箱中完成训练学习。第2 d的睡眠剥夺之后,立即对小鼠进行情景恐惧关联的记忆测试。结果第1 d情景条件恐惧的训练学习阶段,随着足底电击的次数增加,小鼠的冻结时间不断增加,证明了非条件性刺激的有效性;而且对照组、轻柔刺激剥夺组和剥夺杆剥夺组在训练学习阶段的冻结时间百分比差异无统计学意义(t=1.127,P>0.05)。第2 d急性睡眠剥夺后,情景恐惧测试5 min的冻结时间占总时间的比例分别为对照组(50.85±8.92)%、轻柔刺激剥夺组(28.95±12.45)%和剥夺杆剥夺组(43.85±10.52)%。与对照组相比,轻柔刺激剥夺组5 min的总冻结时间显著减少(t=3.227,P<0.05),剥夺杆剥夺组差异无统计学意义(t=1.032,P>0.05);轻柔刺激剥夺组与剥夺杆剥夺组的冻结时间差异无统计学意义(t=2.195,P>0.05)。结论轻柔刺激法诱导急性睡眠剥夺损害雌性小鼠的情景恐惧记忆,而剥夺杆剥夺没有观察到类似现象。

Objective To explore the effects of gentle handling and rotating bar sleep deprivation methods on episodic fear memory in female mice.Methods Fifteen C57BL/6J female mice were randomly divided into control group,gentle handling sleep deprivation group and rotating bar sleep deprivation group,with 5 mice in each group.Among them,the gentle handling sleep deprivation group was established by using gentle handling method,while the rotating bar sleep deprivation group was established by using Pinnacle automatic sleep deprivation system,and the control group stayed in the original cage.The modeling time was from 8 a.m.to 5 p.m.,which lasted for 9 hours,and mice were free to access food and water during this period.On the day before sleep deprivation,mice were put into the training box of four-station conditioned fear system to complete training and learning.After sleep deprivation on the second day,the mice were immediately tested for episodic fear associated memory.Results During the training session on the first day,the freezing time of the mice gradually increased with constant foot shocks,confirming the effectiveness of unconditioned stimulation.Furthermore,there was no statistically significant difference in the percentage of freezing time among the control group,the gentle handling sleep deprivation group,and the rotating bar sleep deprivation group during the training session(t=1.127,P>0.05).After acute sleep deprivation on the second day,the proportion of 5 minutes freezing time in total time of the episodic fear test in the control group,the gentle handling sleep deprivation group and the rotating bar sleep deprivation group were(50.85±8.92)%,(28.95±12.45)%and(43.85±10.52)%,respectively.Compared with the control group,the 5 minutes total freezing time of the gentle handling sleep deprivation group showed significant reduction(t=3.227,P<0.05);while there was no statistical difference in the freezing time between the rotating bar sleep deprivation group and the control group(t=1.032,P>0.05).There was also no significant difference between gentle handling sleep deprivation group and rotating bar sleep deprivation(t=2.195,P>0.05).Conclusions Acute sleep deprivation induced by gentle handling im-paired episodic fear memory in female mice,whereas no such impairment was observed in mice induced by rotating bar sleep deprivation.