两种热应激预处理对热应激小鼠行为学的影响

EFFECT OF DIFFERENT HEAT STRESS PRECONDITIONING ON BEHAVIORS OF MICE IN HEAT STRESS

目的探讨2种不同的热应激预处理对热应激小鼠行为学的影响及机制,为选择最佳热应激预处理模式提供理论依据。方法将试验小鼠随机分为对照组(NC组)、热应激组(HS组)、间歇性热应激预处理组(PHP组)及连续性热应激预处理组(CHP组)。建立小鼠热应激预处理模型,采用穿梭实验法,观察各组小鼠热应激(42℃1、20 min)后6 h1、2 h、24 h不同时间点学习、记忆功能;采用免疫组化法检测各组小鼠大脑皮层nNOS的表达。结果①穿梭实验结果表明:与对照组相比,HS组在6 h1、2 h时错误次数分别为(5.4±1.5)次(、3.9±1.0)次,明显高于对照组〔(2.1±0.8)次、(1.9±0.7次)〕(P<0.05),潜伏期明显缩短(P<0.05)。PHP和CHP组在6 h1、2 h时错误次数分别为(3.8±1.1)次和(3.0±1.4)次、(1.0±0.3)次和(2.4±0.8)次,明显少于HS组(P<0.05)。②nNOS阳性神经元数检测结果表明:与对照组比较,HS组小鼠在6 h、12 h时皮层nNOS阳性细胞数为(80.9±5.9)个(、68.3±8.2)个,明显多于对照组〔(59.40±4.0)个(、59.40±4.0)个〕(P<0.05)。PHP和CHP组皮层nNOS阳性细胞在6 h、12 h时分别为(66.8±4.6)个和(69.0±4.3)个、(58.5±5.8)个和(58.3±3.9)个,明显少于HS组(P<0.05)。结论 2种热应激预处理方式均能对热应激小鼠脑损伤起到保护作用,且保护作用无明显差别。

Objective To explore the effect of different heat stress precinditioning on the behaviors of heat stressed mice so as to provide the theoretical basis to select the best model of heat stress preconditioning. Methods The mice was divided into four groups,norml control（NC） group,heat stress（HS） gerup,periodical heat preconditioning（PHP） group,continuous heat preconditioning（CHP） group.The models of pcriodical and continuous heat stress preconditioning,and heat stress for mice were made.Step-through test were used to evaluate the ability of learning and memory,and immunohistochemisty method to evaluate the expression of nNOS in the cortex of mice at 6 h,12 h,24 h after heat stress.Results ① The step-through test showed that the number of mistake made in HS group at 6 h,and 12 h（5.4±1.5,3.9±1.0 respectively） was more than in control group（2.1±0.8,1.9±0.7）,（P0.05）,but that in PHP group and CHP group at 6 h and 12 h（3.8±1.1,3.0±1.4;1.0±0.3,2.4±0.8） was less than in HS group（P0.05）.② The number of positive nNOS neurons in HS group at 6 h,12 h（80.9±5.9,68.3±8.2） was more than in control group（59.4±4.0,59.4±4.0）,（P0.05）,as well as in PHP and CHP group（66.8±4.6,69.0±4.3;58.5±5.8,58.3±3.9）,（P0.05）.Conclusion Both periodical and continuous heat preconditioning could protect heat stress-induced damage to mice brain,but there is no significant difference between the two methods.