补锌对急性冷应激大鼠解偶联蛋白水平的影响

目的　研究补锌对大鼠耐寒力的影响及其可能机制。方法　雄性SD大鼠 6 0只 ,随机分为 4组 ,1、3组正常进水进食 ,2、4组给予正常饲料 ,饮高锌水 补锌 1mg (kg·d) ],5d后 ,3,4组大鼠于 - 15℃的冷室中暴露 2h ,测各组直肠温度后与 1,2组一同宰杀 ,测定血浆和组织中的锌含量 ;用3 H标记的鸟嘌呤核苷酸 (3 H GTP)与线粒体上解偶联蛋白 (UCP)相结合 ,用液体闪烁仪测定其放射性活性 ,经ScatchardPlot测定出两者结合的解离常数 (Kd)和最大结合量 (Bmax)。结果　未补锌组和补锌组直肠温度下降的幅度分别为 - 2 95± 0 6 1和 - 1 16± 0 39℃ (P <0 0 5 ) ;冷暴露可以增加组织的锌水平 ;补锌组、冷暴露组与对照组相比Bmax增加 ,Kd值无明显差别。结论　适量补锌可以通过增加棕色脂肪组织线粒体中UCP含量提高机体的耐寒力。

Effects of zinc on content of uncoupling protein in cold stress rats

OBJECTIVE: To study effects and regulatory mechanism of zinc on cold stress in rats. METHODS: Sixty male SD rats were randomized into 4 groups. Rats of group I and III drank tap water, group II and IV drank high-zinc water1 mg/(kg.d)], respectively, and 5 days later, rats from group III and IV underwent exposure to cold-15 degrees C for 2 hours. The rectal temperature before and after cold exposure were assayed. Zinc concentration in plasma and tissue were assayed. Radioactivity was measured by liquid glimmer instrument using 3H-GTP binded UCPin mitochondria. The dissociation constant(Kd) and maximal binding(Bmax) was determined from Scathardplot. RESULTS: The decreased range of rectal temperature during cold exposure of group zinc and control were -2.95 +/- 0.61 and -1.16 +/- 0.39(P < 0.05), respectively. There was a significant increase in the content of zinc in the tissue after cold exposure. With zinc and cold treatment, Bmax increased, Kd remained unchanged. CONCLUSION: Zinc might play an important role in cold stress and cold endurance through increase concentration of UCP in brown adipose tissue mitochondria.