中文摘要：

目的：构建梯度热应激大鼠模型，探讨不同程度热应激对大鼠核心体温（Tc）调节以及预后的影响。方法雄性SPF级SD大鼠随机分为正常对照组、41℃组、42℃组、43℃组、44℃组。除正常对照组置于室温环境下外，其余各组大鼠于39℃进行热打击，直肠热电偶测量直肠温度，代表Tc。监测各组大鼠Tc 的变化，频率为10 min/次。41℃、42℃、43℃、44℃组分别达到对应的预设温度41、42、43、44℃时取出大鼠，将大鼠放入环境温度25℃的室温环境下，恢复自由进食、水，并继续监测8 h内Tc 变化，观察72 h内大鼠的生存情况。结果随热应激的程度不同，大鼠T c 呈现不同的特征性改变。热应激期间，41℃和42℃组大鼠表现为双相式T c 上升，而43℃和44℃组大鼠表现为三相式Tc上升。脱离热应激后，41℃和42℃组大鼠Tc 在1 h内恢复正常水平，而43℃和44℃组均出现低Tc ，以44℃组为明显。41℃和42℃组大鼠72 h内未出现死亡，43℃和44℃组出现不同比例的大鼠死亡，生存分析显示，44℃组大鼠预后显著差于43℃组大鼠（ P＜0.01）。结论不同程度热应激对于大鼠Tc 调节特征有显著影响，热应激程度越高，恢复期低Tc 程度越深，预后越差。

英文摘要：

Objective To construct the gradient heat stress rat model and thus to study its influence on core body temperature （ Tc ） during heat stress and prognosis .Methods Male SPF SD rats were randomly divided into normal con-trol group, 41℃group, the 42℃group, 43℃group and 44℃group.Except for normal control group , the rats were ex-posed 39℃heat stress .The rectal thermocouple was used to measure rectal temperature as Tc , which was monitored every 10 min.When the corresponding preset temperatures were reached , the rats in the 41℃, 42℃, 43℃ and 44℃ groups were placed in ambient temperature of 25℃.The Tc was monitored within 8 h, and the survival within 72 h was also recorded.Results With varying degrees of heat stress , the Tc of rats was presented in different patterns .Biphasic rise was observed in 41℃and 42℃groups, while triphasic rise was observed in 43℃and 44℃groups.Out of heat stress, the Tc in 41℃and 42℃groups was returned to normal levels within 1 h, while low Tc was observed in 43℃and 44℃groups, and especially in 44℃group.Deaths were recorded in 43℃and 44℃groups, while significantly worse prognosis was re-vealed in 44℃group according to survival analysis （P〈0.01）.Conclusion Different degrees of heat stress have signi-ficant effect on Tc in rats.The higher degree of heat stress , the lower Tc is presented during the convalescence , suggesting worse prognosis .