同步遥测分析大鼠棕色脂肪产热与体温昼夜节律变化的时间关系

目的：同步遥测棕色脂肪组织（BAT）产热与体核温度昼夜律变化的时间曲线,分析二者昼夜节律变化的时间关系。方法：实验用成年雄性SD大鼠,在22℃环境温度下,明暗时间各12h,昼光时间为06：00h-18：00h,同步无线遥测体核温度（TC）、BAT温度（T队T）、腋窝温度（Tax）和动物活动的昼夜节律变化。结果：①在昼光中,TBAT较TC低0．67％,而在暗光中二者则相似。大鼠从昼光进入暗光时,TBAT升高的速率较TC升高速率快,开始上升的时间较TC提前8min;而从暗光进入昼光时,TBAT开始下降的时间则较TC提前4min。②Tax的昼夜节律幅度与TC相似,但无论动物在明光期或暗光期中,Tax均低于同步测量的TC。③从昼光期转入暗光期时,动物的行为活动出现增加反应先于TBAT和TC开始上升的时间。结论：实验结果证明,在暗光期中大鼠TC升高与BAT产热增加有关,说明BAT昼夜节律性产热的变化在维持体温昼夜生理节律中有重要的作用。

Simultaneous telemetric analyzing of the temporal relationship for the changes of the circadian rhythms of brown adipose tissue thermogenesis and core temperature in the rat

Objective： To measure simultaneously the time course for the circadian rhythm of brown adipose tissue（BAT） thermogenesis and core temperature, and analyzing their temporal relationship. Methods： The circadian rhythm of core temperature（Tc）, BAT temperature （TBAT）, axilary temperature （Tax） and motor activity were simultaneously measured by telemetry in adult male Sprague-Dawley rats at an ambient temperature of 22℃during a 12-h light： 12-h dark photoperiod （lights on at 06：00 h and lights off at 18：00 h）. Results： （1）TBAT Was 0. 67℃ lower than Tc group under the light phase, but it was similar to that Tc during the dark phase. The rate of increase in TBAT was higher than corresponding increases in Tc at the start of transition from the light to dark phase, and increase in TBAT commenced approximately 8 min before Tc increases. Whereas at the start of transition from the dark to light phase, decrease in TBAT commenced approximately 4 rain before Tc decreases. （2）The amplitude of the circadian Tax rhythm was similar to that of Tc. During either the light phase or dark phase, Tax was lower than simultaneous measurement of Tc. （3）Increases in behavioral activity commenced before increases in TBAT and Tc at the start of transition from the light to dark phase. Conclusion： BAT thermogenesis contributes to increase in core temperature during the dark phase, indicating that circadian changes of BAT thermogenesis does indeed play significant role in the overall maintenance of the circadian rhythm of core temperature.