急性缺氧通过抑制臂旁外侧核降低大鼠对寒冷的敏感性

Acute hypoxia blunts cold sensitivity through the inhibition of the lateral parabrachial nucleus in rats

为探讨急性缺氧对寒冷敏感性的影响及其机制,Sprague-Dawley大鼠随机分为常氧对照组(21%O_(2),25℃)、10%O_(2)缺氧组(10%O_(2),25℃)、7%O_(2)缺氧组(7%O_(2),25℃)、常氧寒冷组(21%O_(2),10℃)和缺氧寒冷组(7%O_(2),10℃)。冷撤足实验和两板温度位置偏爱实验测定大鼠冷撤足潜伏期和偏爱温度,红外热像仪测量体表温度,无线遥测系统测定核心体温。免疫组化法检测脑桥臂旁外侧核c-Fos表达。结果显示,急性缺氧可显著延长大鼠的冷撤足潜伏期,显著增强大鼠撤足时的冷刺激强度,并且缺氧大鼠更偏爱寒冷温度;10℃寒冷刺激可显著增强常氧大鼠臂旁外侧核c-Fos表达,而缺氧可抑制寒冷诱导的c-Fos表达;急性缺氧大鼠足部和尾部的皮肤温度显著升高,肩胛间的皮肤温度显著降低,大鼠核心体温显著降低。结果说明,急性缺氧可显著降低大鼠对寒冷的敏感性,其机制可能与脑桥臂旁外侧核受到抑制有关,提示急进高原人群对寒冷的敏感性降低,需主动保暖以防上呼吸道感染和急性高原病的发生。

To explore the changes of cold sensitivity after exposure to acute hypoxia and its mechanisms,Sprague-Dawley rats were divided into normoxia control group(21% O_2,25℃),10% O_(2) hypoxia group(10% O_2,25℃),7% O_(2) hypoxia group(7% O_2,25℃),normoxia cold group(21% O_2,10℃) and hypoxia cold group(7% O_2,10℃).Cold foot withdrawal latency and preference temperature of each group were measured,skin temperatures were estimated using an infrared thermographic imaging camera,body core temperature was recorded by wireless telemetry system,immunohistochemical staining was used to detect the expression of c-Fos in the lateral parabrachial nucleus(LPB).The results showed that acute hypoxia significantly prolonged the latency of cold foot withdrawal and significantly enhanced the intensity of cold stimulation for foot withdrawal,and the rats under hypoxia preferred cold temperature.Cold exposure(10℃) for 1 h significantly enhanced the expression of c-Fos in LPB of rats in normoxia,while hypoxia inhibited cold-induced c-Fos expression.Acute hypoxia significantly increased the skin temperature of feet and tails,decreased the skin temperature of interscapular region,and decreased the body core temperature of rats.These results indicate that acute hypoxia can significantly blunt cold sensitivity through the inhibition of LPB,suggesting actively keeping warm measures should be taken at the early stage after ascent to high altitude to prevent the upper respiratory infection and acute mountain sickness.