蓝光照射对小鼠视网膜形态和功能的损伤作用

目的通过观察蓝光照射对C57BL/6J小鼠视网膜形态和功能的影响,探讨非渗出性年龄相关性黄斑变性(AMD)的模型。方法采用投币法将20只8周龄清洁级C57BL/6J雄性小鼠随机分为正常对照组和蓝光照射组。蓝光照射组小鼠暗适应24 h后暴露于10000 lx蓝光下5 d,正常对照组小鼠按12 h/12 h正常光照/黑暗的周期饲养于正常光照环境5 d。采用光相干断层扫描成像(OCT)活体检查各组小鼠视网膜厚度变化,采用视网膜电图(ERG)检查各组小鼠视网膜功能变化。于光照结束后24 h采用颈椎脱臼法处死小鼠并制备眼球壁标本,采用免疫荧光染色法测定小鼠视网膜中视紫红质(Rho)、紧密连接蛋白(ZO-1)和β-catenin蛋白表达。结果蓝光照射组小鼠视网膜上部和下部距视盘200、400、600、800和1000μm处视网膜外核层厚度均较正常对照组变薄,差异均有统计学意义(均P<0.05)。蓝光照射组小鼠暗适应和明适应b波振幅分别为(305.50±41.52)μV和(119.50±6.67)μV,分别低于正常对照组的(415.50±28.77)μV和(139.75±8.26)μV,差异均有统计学意义(均P<0.05)。正常对照组小鼠RPE细胞呈正六边形,视网膜各层形态规则,Rho、ZO-1和β-catenin荧光较强;蓝光照射组小鼠RPE细胞形态不规则,ZO-1染色减弱或消失,β-catenin染色和Rho蛋白荧光强度减弱。结论蓝光照射小鼠视网膜变薄,视网膜功能减弱。

Damage of blue-light exposure to retinal morphology and function in mice

Objective To study the damage effects of blue-light exposure on retinal morphology and function in mouse.Methods Twenty 8-week-old clean C57BL/6J mice were randomly divided into blue-light exposure group and normal control group by coin tossing method.The mice in the blue-light exposure group was exposed to 10000 lx blue light for 5 days after dark adaptation for 24 hours,and the mice in the normal control group was kept under the normal light intensity for 5 days at 12-hour light/12-hour darkness cycles.The retinal thickness was detected by optical coherence tomography(OCT),and retinal function was evaluated by electroretinogram(ERG).The mice was sacrificed and the frozen section and flat mount of eyeball wall was created at 24 hours after irradiation.The expressions of rhodopsin(Rho),zonula occludens-1(ZO-1)andβ-catenin in the retinas were detected by immunofluorescent staining.The use and care of the experimental animals adhered to ARVO Statement by American Society of Visual and Ophthalmological Sciences(No.IACUC-1803029).Results The thickness of the retinal outer nuclear layer at 200,400,600,800 and 1000μm from the superior and inferior to optic nerves were thinned in the mice of the blue-light exposure group compared with those of the normal control group,showing significant differences between the two groups(all at P<0.05).The b-wave amplitude of the scotopic and photopic ERG was(305.50±41.52)μV and(119.50±6.67)μV in the blue-light exposure group,respectively,which was significantly reduced in comparison with(415.50±28.77)μV and(139.75±8.26)μV of the normal control group(both at P<0.05).Immunofluorescent staining showed that the retinal pigment epithelial(RPE)cells of the mice exhibited hexagonal shape with regular arrangement,retinal morphology was regular,and the expressions of Rho,ZO-1 andβ-catenin proteins showed stronger fluorescence in the retinas of normal control group.However,structural disorder,diminishing fluorescence intensity of Rho,ZO-1 andβ-catenin were found in the blue-light exposure group.The morphology of the retina was disordered while the cell structure was destroyed.Conclusions Blue-light irradiation results in morphological and functional damages of retina.