茶多酚EGCG对小鼠棕色脂肪代谢的影响

 随着对棕色脂肪组织（BAT）在成人体内具有生物学功能的肯定，棕色脂肪已经成为当今医学研究的热点。采用动物实验、病理组织学方法及免疫组化，观察了表没食子儿茶素没食子酸酯（EGCG）对棕色脂肪代谢的影响。结果表明，在体重和鼠龄相近时，不同种属小鼠肩甲间棕色脂肪组织HE 染色后的形态不同，C57BL/6 脂肪细胞中的空泡大，胞浆含量少，BALB/c 小鼠脂肪细胞中的空泡小，胞浆含量多，昆明小鼠居中。给昆明小鼠口服不同剂量EGCG 后，150 mg/kg EGCG 能降低小鼠体重的增长，降低附睾周围白色脂肪组织的重量，但没有统计学意义。同时，EGCG 能降低棕色脂肪细胞内脂肪含量，增加胞浆含量，具有统计学意义（P<0.001）。免疫组化结果表明，EGCG 能增加棕色脂肪细胞内脱偶联蛋白1（UCP1）的表达，增加能量代谢。因此，不同种属小鼠的BAT 具有不同的组织形态学特点，这为研究BAT 小鼠的选择提供了依据；EGCG 能够调节小鼠棕色脂肪的代谢功能，这为进一步研究作用机制打下了基础，同时为茶叶在脂肪代谢方面的调节提供了一种新的思路和依据。

Effects of Tea Polyphenol EGCG on the Metabolism of Brown Adipose Tissue in Mice

With recognition of biological functions of brown adipose tissue (BAT) in adults, it has become a hot topic in medical research. In the present study, the effects of (-)-Epigallocatechin-3-gallate(EGCG) on the metabolism of BAT are investigated through animal experiments, histopathologicaland immunohistochemical methods. The results show that there are disparities in morphology of interscapular BAT among different species of mice. Vacuoles of fat droplets in adipocytes of C57BL/6 mice are the largest, and the cytoplasmic content is the least. Vacuoles in adipocytes of BALB/c mice are the smallest, and the cytoplasmic content is the most. Vacuoles and cytoplasmic content in Kunming mice lie between those in C57BL/6 and BALB/c mice. EGCG at 150 mg/kg decreases the increment rate of body weight and reduces the weights of epididymal white adipose tissue, but there is no statistical significance after different doses of EGCG are administered p.o. to Kunming mice. EGCG significantly decreases the content of fat (shown as vacuoles in the sections) in BAT and increases the cytoplasmic content (P<0.001). By immunohistochemical examination, EGCG increases the expression level of uncoupling protein 1, indicating the increase of energymetabolism in BAT. Therefore, there exist diversemorphological characteristics in different inbred lines of mice, which provides the basis for selection of mice in BAT studies. EGCG may regulate the metabolism of BAT in mice, which lays the foundation for further studies of its mechanism and provides new ideas for studies of the regulation of fat metabolism by tea.