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目的观察间歇性冷刺激对大鼠耐寒能力的影响。方法雄性SD大鼠12只,按体重(110±5)g随机平均分为对照组(n=3)、间歇性冷刺激组(n=3)、急性冷暴露组(n=3)和间歇性冷刺激并急性冷暴露组(n=3)。间歇性冷刺激组(3 w)与间歇性冷刺激并急性冷暴露组(3 w+cold)接受4℃,4 h/d冷刺激,共21 d;对照组(con)和急性冷暴露组(cold)进行室温饲养。3周后,cold和3 w+cold组在第2 d接受-15℃,4 h冷暴露,观察大鼠肛温变化及棕色脂肪组织形态和功能的改变。结果 -15℃冷暴露4 h导致急性冷暴露组(cold)大鼠肛温明显下降(P<0.05),下降(2.64±0.182)℃,而间歇性冷刺激并急性冷暴露组(3 w+cold)大鼠肛温无明显改变,下降(0.32±0.531)℃;棕色脂肪组织形态观察显示:急性冷暴露组(cold)大鼠肩胛间区棕色脂肪面积较小边界不清,充血明显,色泽呈暗红色,间歇性冷刺激并急性冷暴露组(3 w+cold)肩胛间区棕色脂肪面积较大,边界较清晰,充血明显,色泽呈深棕色。Western blot检测发现,间歇性冷刺激可使大鼠棕色脂肪组织线粒体CoxⅣ及解耦连蛋白1(UCP1)含量明显升高。结论 21 d间歇性冷刺激可以显著提高大鼠耐寒能力,棕色脂肪组织形成、线粒体CoxⅣ和UCP1含量增加可能是其耐寒能力提高的主要因素。
Objective To observe the effect of intermittent cold stimulation on cold tolerance in rats. Methods Twelve male SD rats were randomly divided into control group (n = 3), intermittent cold stimulation group (n = 3), acute cold exposure group (n = 3) Cold stimulation and acute cold exposure group (n = 3). The rats in intermittent cold stimulation group (3 w) and intermittent cold stimulation group (3 w + cold) received cold stimulation at 4 ℃ for 4 h / d for 21 days. The control group (con) and acute cold exposure group (cold) for room temperature feeding. After 3 weeks, cold and 3 w + cold groups received cold exposure at -15 ℃ and 4 h on the second day, respectively. The change of rectal temperature and morphological and functional changes of brown adipose tissue in rats were observed. Results The cold temperature at -15 ℃ for 4 h resulted in a significant decrease in rectal temperature (2.64 ± 0.182) ℃ in acute cold-exposed rats, while intermittent cold stimulation (3 w + cold (0.32 ± 0.531) ℃. The morphological observation of brown adipose tissue showed that the area of brown fat in the interscapular area of acute cold-exposed rats was small with unclear border, obvious congestion and obvious color Dark red, intermittent cold stimulation and acute cold exposure group (3 w + cold) interscapular area brown fat larger, more clear boundary, congestion was obvious, dark brown color. Western blot showed that intermittent cold stimulation significantly increased the content of mitochondrial CoxⅣ and uncoupling protein 1 (UCP1) in the brown adipose tissue of rats. Conclusion Intermittent cold stimulation at 21 d can significantly increase the ability of cold tolerance, formation of brown adipose tissue, and increase of mitochondrial Cox Ⅳ and UCP1 in the rats.