氢醌诱导小鼠年龄相关性黄斑变性模型的建立

Establishment of hydroquinone induced age-related macular degeneration model in mice

目的观察氢醌诱导小鼠年龄相关性黄斑变性(age-related macular degeneration,AMD)动物模型的病理特征及超微结构改变,为AMD发病机制及防治研究提供模型选择和依据。方法 6~7个月龄C57BL/6小鼠16只随机分为模型组和正常组,每组8只。模型组小鼠被喂以基于基础纯净合成的含8 g·L^(-1)氢醌的饮食,正常组小鼠被喂以不含氢醌的同配方饮食,饲养5个月。采用组织病理学、TUNEL方法和8-OHd G免疫荧光法观察两组小鼠视网膜的结构改变、视网膜色素上皮(retinal pigment epithelium,RPE)细胞的凋亡和DNA损伤情况,透射电镜观察超微结构的改变。结果正常组RPE细胞数目为(7.05±1.54)个,模型组RPE细胞数目为(3.90±1.21)个,模型组RPE细胞数量较正常组显著减少(P<0.01)。透射电子显微镜显示,正常组RPE细胞质中含有丰富的线粒体,较多的色素颗粒,细胞顶部微绒毛数目多且较长;Bruch膜结构规整,厚度均匀。模型组RPE细胞微绒毛变短,Bruch膜不规则增厚,外胶原层见层状沉积物,呈纤丝状及无定形状。TUNEL结果显示,模型组可见较多RPE细胞凋亡,凋亡率为(7.75±3.76)%,内、外核层散在细胞凋亡,正常组未见细胞凋亡,两组差异有显著统计学意义(P<0.01)。8-OHd G结果显示,模型组RPE细胞可见较多的8-OHd G阳性染色,RPE细胞DNA损伤率为(33.35±11.16)%,内、外核层散在阳性染色,正常组RPE细胞散在微弱的8-OHd G表达,DNA损伤率为(0.84±1.78)%,内、外核层未见阳性染色,2组比较差异有显著统计学意义(P<0.01)。结论含氢醌饲料喂养的小鼠具有早、中期AMD的病变特征,可为进一步防治早、中期AMD研究提供可靠的动物模型。

Objective To observe histology and ultrastructure changes of hydroquinone（ HQ） induced animal model with age-related macular degeneration（ AMD）,and provide important information for the further study of AMD. Methods Six to seven months old female C57 BL/6 mice were divided randomly into two groups： model group and normal group,eight mice in each group. The model group were fed with foods containing 8 g · L-1HQ for five months. Normal mice were considered as the normal control without HQ. The retinal pathologic and ultrastructural retinal pigment epithelium（ RPE）-Bruch membrane-choroid changes were observed by light and electron microscopy,and the apoptosis and DNA damage rates of RPE cell were determined by TU NEL and 8-OHd G. Results RPE number in the normal group was 7.05 ± 1. 54,which was more than that in the model group（ 3. 90 ± 1. 21）,there was significant difference between two groups（ P 〈 0. 01）. RPE cells of the model group were not intact and irregular with vacuoles and pigment disorder. The nucleuses were irregular that look like oval or kidney shape. By transmission electron microscopy,cytoplasmic vacuoles were observed in RPE cells of the model group. Bruch membrane show ed amorphous outer collagenous layer deposits and was thicker than the normal group,and amorphous outer collagenous layer deposits were also seen. U sing TU NEL labeling,there were apoptosis of RPE cells and cells of inner and outer nuclear layer in the model group. The apoptosis rate of RPE cells were（ 7. 75 ± 3. 76） %. No apoptosis were found in the normal group. There was significant difference between the two groups（ P 〈 0. 01）. Besides,expression of 8-OHdG in RPE cells was found. The DNA damage rate were（ 0. 84 ± 1. 78） % and（ 33. 35 ± 11. 16） % in the normal and model group. Statistically,there was significant difference between them（ P 〈 0. 01）. Conclusion The mice fed with HQ have the features of early and medium stage AMD,and can be used as an ideal animal model to prevent early and medium stage AMD.