足底电击应激时程对大鼠焦虑样行为的影响

目的观察足底电击应激时程对大鼠高架十字迷宫及开场实验焦虑样行为的影响。方法选取成年雄性SD大鼠按照体重分层随机分为对照组和足底电击组,每组12只。足底电击组予以不可逃避性足底电击(0.8 m A,电击10 s,休息20 s,共5 min,1次/d)结合孤养建立大鼠焦虑模型。分别在足底电击7 d及14 d后测高架十字迷宫和开场实验,评估大鼠的焦虑行为。结果 7 d及14 d足底电击后,足底电击组焦虑样行为增加,差异具有显著意义(P0.01),入臂总次数明显低于对照组,运动活性降低。开场实验足底电击组进入中心区次数及中心区逗留时间低于对照组(P0.01),运动总距离、直立次数及理毛次数足底电击组均明显低于对照组(P0.01),运动探索活性降低。比较7天及14天足底电击组行为学结果,可见随着造模天数的增加,大鼠闭臂时间比及闭臂次数比呈现下降趋势(P0.05),焦虑程度降低。开场实验运动总距离、直立次数及理毛次数14 d低于7d,差异具有显著性(P0.05),提示大鼠运动探索行为进一步减少,自我关注度降低,抑郁样行为增加。结论不同时程的足底电击应激导致大鼠焦虑样行为,影响大鼠运动探索活性。随着造模天数的增加,大鼠行为可能从焦虑样向抑郁样改变。足底电击应激焦虑模型造模时程的选择7 d优于14 d。

The influence of footshock stress duration on anxiety-like behavior in rats

Objective To study the influence of footshock (FS) -stress duration on anxiety-like behavior in the elevated plus-maze and open-field tests. Methods Rats (24) were randomly divided into 2 groups: the control group and the FS group. In the FS group, the anxiety model of rat was produced by inevitability footshock (5 minutes in total, once a day; 0.8mA, lasted for 10 seconds, 20 seconds interval) combined with separation. Anxiety-like behavior was evaluated by elevated plus maze and open-field tests after 7 and 14 days of FS-stress. Results After 7 days and 14 days of FS-stress, FS group showed significantly enhanced anxiety-like behavior and reduced locomotion indicated by total entries as compared to the control group (P < 0.01). In the open field test, the entrance times and the retention time in the central zone, the total movement distance, the numbers of rears and grooming in rats in the FS group were lower than those in the control group, which showed lower locomotion and exploratory activity in the FS groups (P < 0.01,P < 0.05).Compared to 7 days of FS-stress, both CT% (the percentage of time spent in the close arm) and CE% (the percentage of entries to the close arm) were reduced after 14 days of FS-stress showing the decreasing anxiety (P < 0.05), as well as the total movement distance and the numbers of rears and grooming (P < 0.05). The reduced locomotion and exploratory activity and self-regarding in the FS group demonstrated the enhanced depression-like behavior in rats.Conclusions Chronic FS-stress contributes to lower locomotion and exploratory activity in rats and leads to anxiety-like behavior in rats. The increased duration of chronic FS-stress may lead to the behavior change from anxiety-like behavior to depression-like behavior, and 7-days is better than 14-days in making the anxiety model in rats.