亚低温预处理对不安全大深度快速上浮脱险大鼠生存率的影响

The effect of subhypothermia preconditioning on survival rate of rats after great deep abnormal fast buoyancy ascent escape

目的观察亚低温(hypothermia)预处理对不安全大深度快速上浮脱险(AFBAE)大鼠生存率的影响。方法选取120只9周龄健康雄性SD大鼠,按照随机数字表法分为正常室温组(CON组)、亚低温再恢复组(H/R组)和持续亚低温组(H组),每组40只。CON组大鼠暴露于正常室温环境[(24.0±2.0)℃];H/R组大鼠暴露于低温环境[(18.0±2.0)℃]10 min,然后回复到正常室温环境10 min;H组大鼠暴露于低温环境10 min。暴露结束后,3组大鼠均接受150 m的AFBAE模拟实验,并观察出舱30 min后的大鼠存活情况。选取不同环境温度,检测大鼠的肛温和心率。结果CON组大鼠出舱30 min后的存活率为40%,明显低于H/R组(75%)和H组(80%),差异有统计学意义(P<0.05)。H/R组和H组之间的大鼠存活率差异无统计学意义(P>0.05)。环境温度20.0℃以下时大鼠肛温为31.0~36.0℃,明显低于环境温度20.0℃以上时大鼠肛温[(35.0~38.0)℃],差异有统计学意义(P<0.05)。环境温度为19.6℃时大鼠的心率显著高于正常室温(23.5℃)的大鼠,差异有统计学意义(P<0.05)。结论亚低温预处理可提高AFBAE大鼠的存活率,可能与亚低温导致的大鼠心率加快有关。

Objective To observe the effect of sub-hypothermia preconditioning on the survival rate of rats after great deep abnormal fast buoyancy ascent escape(AFBAE).Methods A total of 1209-week-old healthy male SD rats were selected and divided into normal room temperature group(CON group),subhypothermia recovery group(H/R group),and sustained subhypothermia group(H group)by the random number table method,with 40 rats in each group.The rats in the CON group were exposed to normal room temperature(24.0±2.0)℃.The rats in the H/R group were exposed to low temperature(18.0±2.0)℃for 10 minutes,which were then recovered to normal room temperature for 10 minutes.The rats in the H group were exposed to low temperature for 10 minutes.After exposure,all the rats in the three groups underwent a simulated 150 m AFBAE,and the survival of rats was observed 30 minutes after exiting the cabin.The rectal temperature and heart rate of rats were measured at different ambient temperatures.Results The survival rate of rats in the CON group 30 minutes after exiting the cabin was 40%,which was significantly lower than those in the H/R group(75%)and the H group(80%),and the differences were statistically significant(P<0.05).There was no significant difference in survival rate of rat between the H/R group and the H group(P>0.05).The rectal temperature of rats was(31.0-36.0)℃when the ambient temperature was below 20.0℃,which was significantly lower than that(35.0-38.0)℃of rats at an ambient temperature above 20.0℃,and the difference was statistically significant(P<0.05).The heart rate of rats at the ambient temperature of 19.6℃was significantly higher than that of rats at normal room temperature(23.5℃),and the difference was statistically significant(P<0.05).Conclusion Subhypothermia preconditioning can improve the survival rate of rats in AFBAE,which may be related to the increase of heart rate caused by subhypothermia.