冷暴露对中缅树鼩适应性产热特征的影响

在冷暴露(5 ± 1℃)1 d,7 d,14 d 和21d 对中缅树鼩的肝脏、心脏、膈肌、腓肠肌和褐色脂肪组织(BAT)的总蛋白和线粒体蛋白含量、线粒体的状态Ⅳ呼吸能力、细胞色素C 氧化酶活力及血清中甲状腺激素的水平等指标进行了测定。结果表明:冷暴露过程中肝脏线粒体蛋白含量对低温的反应比总蛋白的反应剧烈,心脏和BAT 组织的线粒体蛋白含量也随着冷驯化时间的延长而显著增加,但腓肠肌的反应较为温和;各组织线粒体的状态Ⅳ呼吸能力均显著增强,除腓肠肌外其它各组织细胞色素C 氧化酶活性也随冷暴露时间的延长而急剧增加。说明在低温条件下,肝脏、腓肠肌、心脏和BAT 等组织都参与了体温调节的过程,在自然生境中,低温是重要的刺激产热的调节因子。

Effects of long-term cold-exposure on adaptive thermogenesis in the tree shrew (Tupaia belangeri)

The total protein contents,mitochondrial protein contents,state Ⅳ respiratory ability,respiration control ratio
(RCR),Cytochrome C oxidase activity of liver,heart,musculus diaphragma gastrocnemius and brown adipose tissue (BAT) in tree shrews (Tupaia belangeri) and serum thyroid hormone levels were measured during cold exposure (5 ± 1℃)for 1 day,7 days,14 days and 21 days. The results showed that the change of liver mitochondrial protein content was more acute than that for total protein. The mitochondrial protein content of heart and BAT were significantly increased during cold-exposure,however,the reaction of gastrocnemius was more moderate. The state IV mitochondrial respiration of these tissues increased more than did those of the control. The cytochrome C oxidase activity with cold acclimation also significantly increased for all except the gastrocnemius. Liver,gastrocnemius,BAT,heart and other organs were involved in thermoregulation during the thermal regulation process during cold-exposure. Therefore,cold-stress was an important stimulus regulator of the natural environment.