表没食子儿茶素没食子酸酯对中波紫外线诱导小鼠皮肤黑素小体转移与降解的影响  

Effect of epigallocatechin gallate on ultraviolet B-induced transfer and degradation of melanosomes in mice

作　　者：贾肖肖 胡文婷 王敏 华优 高亚丽 耿清伟 李刘雨 宋秀祖 

机构地区：[1]浙江中医药大学附属杭州第三医院杭州市第三人民医院皮肤科,杭州310009

出　　处：《中华皮肤科杂志》2017年第12期863-868,共6页Chinese Journal of Dermatology

基　　金：国家自然科学基金（81000697）;杭州市科技发展计划项目（20130733Q24）

摘　　要：的 观察茶多酚单体表没食子儿茶素没食子酸酯（EGCG）对中波紫外线（UVB）诱导小鼠皮肤色素沉着及黑素小体转移和降解的影响，探讨自噬在其中的作用机制。方法 将16只C57/BL6雌性小鼠32只鼠耳用简单随机方法随机等分为4组：①丙酮对照组：每日予丙酮溶液外涂耳部皮肤；②EGCG组：每日予10 g/L EGCG丙酮溶液外涂；③UVB照射组：单次500 mJ/cm2 UVB照射，照射2 h后每日外涂丙酮溶液；④UVB ＋ EGCG组：单次UVB照射2 h后每日外涂EGCG丙酮溶液。10 d后处死小鼠，收集耳部皮肤，透射电镜观察黑素小体及自噬体超微结构变化，免疫组化法检测蛋白酶活性受体2（PAR2）及微管相关蛋白轻链3（LC3）在表皮中的表达，免疫印迹法检测PAR2、Rab27a及LC3在表皮中的表达。结果 丙酮对照组、UVB照射组、UVB ＋ EGCG组和EGCG组间黑素小体及自噬体数量差异均有统计学意义（H值分别为12.249、13.888，均P 〈 0.05）；与丙酮对照组小鼠皮肤角质形成细胞内黑素小体数量（1.00 ± 0.41）、自噬体数量（1.00 ± 0.46）相比，UVB照射组黑素小体（1.85 ± 0.32）和自噬体（1.94 ± 0.64）均显著增加（均P＜0.05）；相较于UVB照射组，UVB ＋ EGCG组黑素小体（1.30 ± 0.44）显著减少（P＜0.05），而自噬体（3.03 ± 0.75）则明显增加（P＜0.05）。免疫组化显示，4组间PAR2在表皮中的表达差异有统计学意义（H = 18.700，P 〈 0.05）；与UVB照射组（12.54 ± 3.07）比较，UVB ＋ EGCG组PAR2表达（7.94 ± 4.57）显著减少（Z = 2.143，P 〈 0.05）；但4组表皮LC3表达均不明显，表达水平差异无统计学意义（H = 5.051，P＞0.05）。免疫印迹显示，4组间PAR2、Rab27a表达及LC3Ⅱ/LC3Ⅰ比值差异均有统计学意义（F值分别为18.739、25.967、24.022，均P 〈 0.05）；与UVB照射组（PAR2 3.12 ± 0.61，Rab27a 1.42 ± 0.07，LC3Ⅱ/ LC3Ⅰ1.24 ± 0.07）比较，UVB ＋ EGCG组PARObjective To evaluate the effect of tea polyphenol epigallocatechin gallate（EGCG）on ultraviolet B （UVB）-induced skin pigmentation, transfer and degradation of melanosomes in mice, and to explore the role of autophagy in the mechanism of melanosome degradation. Methods A total of 32 ears from 16 female C57/BL6 mice were randomly and equally divided into 4 groups： acetone control group topically treated with acetone solution daily, EGCG group topically treated with 10 g/L EGCG acetone solution daily, UVB irradiation group irradiated with 500 mJ/cm2 UVB once a day and 2 hours later topically treated with acetone solution, UVB ＋ EGCG group irradiated with 500 mJ/cm2 UVB once a day and 2 hours later topically treated with EGCG acetone solution. Ten days later, all the mice were sacrificed, and skin tissue samples were collected from the ears. Transmission electron microscopy was performed to observe ultrastructural changes of melanosomes and autophagosomes, immunohistochemical study to measure of protease-activated receptor 2 （PAR2） and microtubule-associated protein light chain 3 （LC3） in the epidermis, and Western blot analysis to determine the protein of PAR2, Ras-related protein Rab27a and LC3 in the epidermis. Results There was a significant difference in the number of melanosomes and autophagosomes among the acetone control group, EGCG group, UVB irradiation group and UVB ＋ EGCG group （H = 12.249, 13.888, respectively, both P 〈 0.05）. Compared with the acetone control group, the UVB irradiation group showed significantly increased number of melanosomes （1.85 ± 0.32 vs. 1.00 ± 0.41, P 〈 0.05）and autophagosomes （1.94 ± 0.64 vs.1.00 ± 0.46, P 〈 0.05） in epidermal keratinocytes in mouse skin. Compared with the UVB irradiation group, the UVB ＋ EGCG group showed significantly decreased number of melanosomes（1.30 ± 0.44, P 〈 0.05）, but significantly increased number of autophagosomes（3.03 ± 0.75, P 〈 0.05）. Immunohistochemical study showed a significant differ

关 键 词：多酚类 紫外线 自噬 黑素类 表没食子儿茶素没食子酸酯 

分 类 号：R751[医药卫生—皮肤病学与性病学]