慢性不可预见应激大鼠模型的改进

Improvement of rat model induced by chronic unpredicted stress

目的:对慢性不可预见应激大鼠模型建立方法进行改进,观察能否获得成功率更高、行为学变化更明显的抑郁动物模型。方法:54只雄性SD大鼠随机分为正常对照组(NC)、慢性不可预见应激组(CUS)、改良慢性不可预见应激组(ICUS),每组18只。NC组正常饲养不给予任何应激;CUS组每天从9种应激中随机选取1种应激作用于大鼠,持续6周;ICUS组在实验前3周每天从9种应激中随机选取1种应激作用于大鼠,在实验后3周每天从9种应激中随机选取2种应激作用于大鼠。实验第5和6周结束时,行糖水偏爱实验(SPT)、矿场实验(OFT)、强迫游泳实验(FST)。NC组大鼠两次测量值均未偏离基础值10%以上纳入分析,CUS和ICUS组2次测量值均偏离基础值10%以上纳入分析。结果:NC、CUS和ICUS组最后符合条件大鼠分别为15只(83.3%),9只(50.0%)和14只(77.8%)。糖水偏爱实验发现:与NC组比较,CUS和ICUS组大鼠蔗糖消耗百分比明显降低(P<0.01);与CUS组比较,ICUS组大鼠蔗糖消耗百分比进一步降低(P<0.05)。强迫游泳实验发现:与NC组比较,CUS和ICUS组大鼠两次大鼠不动时间测量值均明显延长(P<0.01);与CUS组比较,ICUS组大鼠两次大鼠不动时间测量值进一步延长(P<0.05)。矿场实验发现:CUS和ICUS组大鼠活动测量值明显低于NC组(P<0.01),但CUS和ICUS组大鼠横向及纵向运动穿格数差异无统计学意义。结论:改良的慢性不可预见应激大鼠模型建立方法可获得成功率更高和行为学变化更明显的抑郁动物模型。

Objective： To investigate the possibility of improving the depressive rat model induced by chronic unpredicted stress in order to obtain higher successful rate and better behavoir phenotype. Methods： Fifty-four male Sprague-Dawley rats were randomly divided into normal control（ NC）, chronic unpredicted stress（ CUS）,and improved chronic unpredicted stress（ ICUS） group, with 18 rats in each group. Rats in NC group were normally fed and did not receive any stimulus. The rats in CUS group were randomly received one of nine stressors per day for 6 weeks, and rats in ICUS group were randomly given one of nine stressors per day in the first three weeks and two of nine stressors per day in the last three weeks. In the fifth and sixth weeks, rats were given a series of behavior tests including sucrose preference test（ SPT）, open field test（ OFT）, and forced swim test（ FST）. The rats were included if the value of the both tests was either less or more than 10% of baseline values in the NC or CUM/ICUM group respectively. Results： There were 15（ 83.3%）, 9（ 50.0%）, and 14（77.8%） rats meeting the including criteria in the NC, CUS, and ICUS group, respectively. SPT indicated that the percentage of sugar consumption in the CUS and ICUS-treated rats was markedly less than those in NC group（P〈0.01）, ICUS-treated rats also exhibited a significant decrease in the percentage of sugar consumption compared with CUS-treated rats（P〈0.05）. FST indicated that CUS and ICUS-treated rats had a more significant increase in immobility time than that in NC-treated rats（P〈0.01）, ICUS-treated rats also exhibited a significant increase in immobility time compared with CUS-treated rats（P〈0.05）. OFT indicated that CUS and ICUS-treated rats had a more significant reduction in locomotor activity than that in NC-treated rats（P〈0.01）. However, there was no statistical difference between CUS- and ICUS-treated rats in the OFT. Conclusion： ICUS method can build higher success rate and better behavior phenotypes in the animal model induced by chronic unpredicted stress.