Müller细胞在视网膜绿光损伤模型中的激活反应

Activation of Müller cells in the green light damaged retina

目的研究Müller细胞在大鼠视网膜绿光损伤模型中的激活反应。方法 72只出生后8周(约230～280g)的成年雄性Sprague-Dawley大鼠随机分9组。一组作为正常对照,另8组暗适应24 h后置于波长为(530±10)nm的LED灯光箱中照射3 h,并分别于暗恢复3、6、12 h及1、2、3、7、15 d取眼球,光学显微镜下观察同一定位处视网膜组织形态、检测(TUNEL)凋亡细胞、免疫组织化学染色及蛋白免疫印迹分析。结果光损伤后光感受器内外节变短,外核层变薄,细胞排列紊乱;细胞凋亡出现在外核层,暗恢复3 h出现,3 d时达到高峰,7 d时消失;胶质细胞纤维酸性蛋白(glial fibrillary acidic protein,GFAP)表达量于暗恢复12 h开始升高,随暗恢复时间延长逐渐升高;谷氨酰胺合成酶(glutaminesynthetase,GS)总表达量未见明显改变,但可见蛋白一过性重分布,表达部位由内核层移至外核层。pSTAT3蛋白表达量于损伤后12 h出现一过性升高。结论绿光损伤视网膜激活Müller细胞,pSTAT3可能参与了此激活过程。

Objective To investigate the reaction of Müller cells in green light damaged retina.Methods Dark-adapted 8 week-old albino rats were exposed to green light for 3 hours at an intensity of 1 mW/cm2,and at different dark recovery intervals,ranging from 3 hours to 15 days,and the the eyes were enucleated.Sections of the retina were taken vertically and the superior parts were examined by histology.Immunocytochemistry and Western blotting were performed to detect the expression and localization of glial fibrillary acidic protein（GFAP）,glutamine synthetase（GS） and phosphated signal transducer and activator of transcription 3（pSTAT3）.TdT-mediated dUTP nick-end labeling（TUNEL） was performed to detect the apoptotic cells.Results In the damaged retina,the rod outer segments（ROS） were shortened and the outer nuclear layer was thinned with the presence of apoptotic cells.According to immunocytochemistry and Western blot analysis,GFAP protein levels increased at 12 hours after injury in the observation period.GS expression remained stable after the light damage.However,during the 7-d period post-injury the GS protein appeared to translocate from the cells in the inner nuclear layer to the cells in the outer nuclear layer.pSTAT3 expression showed a transient increase at 12 hours after injury.Conclusions Green light exposure induces apoptosis in the outer nuclear layer.Müller cells are activated with GFAP expression elevation and GS translocation.pSTAT3 may play a role in triggering GFAP expression in the Müller cells.