内质网应激反应蛋白在光照损伤诱导视网膜变性中的作用  

Activation of endoplasmic reticulum stress proteins in light-induced retinal degeneration

作　　者：吴乐萌[1] 郭秀娟[1] 曹安民[1] 杨丽萍[1] 

机构地区：[1]北京大学第三医院眼科,北京大学眼科中心,北京100083

出　　处：《北京大学学报（医学版）》2008年第4期425-430,共6页Journal of Peking University:Health Sciences

基　　金：国家自然科学基金(30600689)资助~~

摘　　要：目的：探讨在光照损伤诱导视网膜感光细胞变性凋亡中,内质网应激反应蛋白的表达变化。方法：取4 -5周龄的Balb/cJ雄性小鼠189只,随机分为7组（每组n=27）,其中1组（27只）作为对照组,6组（162只）作为实验组。将实验组Balb/cJ小鼠暗适应48h后暴露于光照损伤（波长490 -580nm,光照度3500lx）24h。分别于暗恢复后0h,3h,6h,24h,3d以及7d处死小鼠,摘取眼球。用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（terminal transferase-mediated dUTP nick end labeling,TUNEL）检测感光细胞的凋亡;Western blot检验视网膜中内质网应激反应蛋白（GRP78/BiP,procaspase-12和cleaved caspase-12,p-PERK,p-eIF2α）的表达变化;免疫荧光染色共聚焦显微镜观测内质网应激反应蛋白在视网膜中的表达。结果：（1）光照损伤后视网膜外核层中出现TUNEL染色阳性细胞,并且在暗恢复24h后阳性染色细胞数达到高峰;（2）伴随光照损伤诱导的视网膜变性过程,Western blot检测结果显示内质网应激反应蛋白的表达上调,与正常对照组之间的差异具有统计学意义（P〈0.01）;（3）免疫荧光染色结果显示内质网应激反应蛋白主要表达于视网膜感光细胞的内节和感光细胞核中。结论：在光照损伤诱导的视网膜感光细胞变性凋亡中,内质网应激反应蛋白的激活对于感光细胞的变性凋亡可能具有重要作用。应用内质网应激反应调节剂可能对此类疾病起到有效治疗作用。Objectlve：To investigate the expression of endoplasmic reticulum stress proteins in photoreceptor apoptosis in light-induced retinal degeneration. Methods： Exposure to excessive levels of light induced photoreceptor apoptosis and had been previously used as a model for the study of retinal degeneration. Photoreceptor apoptosis was detected by terminal dUTP transferase nick end labeling （TUNEL）. The protein expression levels of ER stress sensors including glucose-regulated protein-78 （GRP78/BiP）, caspase-12, phospho-eukaryotic initiation factor 2α（eIF2α） and phospho-double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase （PERK） were examined by immunofluorescence and Western blot analysis. Results： Following light exposure, the protein expression levels of GRP78/BiP, caspase-12, phospho-eIF2α and phospho-PERK were up-regulated in a time dependent manner. The up-regulation of these proteins coincided with or preceded the photoreceptor apoptosis. At the peak of their expression, they were mainly located in the photoreceptor inner segments and/or outer nuclear layers （0NL）. Conclusion. Activation of endoplasmic reticulum stress proteins appears to play an important role in light-induced retinal degeneration. Therefore endoplasmic reticulum stress modulators could become a strong candidate for a therapeutic agent in treatment of these diseases.

关 键 词：视网膜变性 内质网 细胞凋亡 光刺激 

分 类 号：R774.13[医药卫生—眼科]