黄斑变性模型 z-bo 2020-12-30 351

　　Objective: To induce the establishment of a mouse age-related macular degeneration model by chronic light combined with hydroquinone feeding, observe its pathological characteristics, ultrastructure and retinal function changes, and provide a new model for the pathogenesis and prevention of AMD.

　　Method: 20 4-month-old C57BL/6 mice were randomly divided into model group and normal group, with 10 mice in each group. The mice in the model group were fed a diet based on basic purity synthesis containing 8g/(kg·bw) hydroquinone, and received 12 hours of light with an intensity of 2500lx a day. The mice in the normal group were fed the same formula diet without hydroquinone, under normal lighting, and reared for 3.5 months. Electroretinogram (ERG), light microscopy and electron microscopy were used to observe the changes in the function and structure of the retina of the two groups of mice. The TUNEL method was used to observe the apoptosis of retinal cells, and the immunofluorescence method was used to detect the retina and choroidal vascular endothelial growth factor (VEGF) and CD31 Expression and distribution.

　　Results: The ERG test results showed that the retinal function of the model group was lower than that of the normal group; light microscope observation showed that the retinal pigment epithelium of the model group showed atrophy-like changes, the Bruch membrane structure was destroyed, and neovascular-like tissue cells grew in and photoreceptor cells were visible. The number of mice in the model group was (164.67±34.37), the normal group was (243.33±15.23), the number of photoreceptor cells in the model group was significantly reduced compared with the normal group, and the difference was statistically significant (t=-9.77, P<0.05); transmission electron The microscope showed that the membrane disc structure of the photoreceptor cells in the model group's retina was loosely deformed and partially fragmented. The microvilli of RPE cells became shorter, the Bruch membrane was irregularly thickened, the outer collagen layer saw laminar deposits, and the endothelial cells protruded into Bruch's membrane. TUNEL results showed that there were almost no apoptotic cells in the normal group, and a large number of apoptotic cells appeared in the retinal pigment epithelial (RPE) layer and photoreceptor cell layer of the model group. The photoreceptor apoptosis rate was (43±2.73)%, and the difference between the two groups was statistically significant. Significance (P<0.01). The immunofluorescence results showed that there were scattered weak positive expressions of VEGF in the outer plexiform layer and nerve fiber layer of the normal group. In addition to the above cells in the model group, strong positive staining was also seen in the RPE cell layer. There was no clear CD31 positive staining in the cells of each layer of the retina in the normal group, and strong CD31 expression was seen in the RPE cell layer of the model group, suggesting that the RPE layer was neovascularization.

　　Conclusion: The mice fed with chronic light combined with hydroquinone feed are very close to the pathogenesis and characteristics of human AMD, which can provide a reliable animal model for further research on the pathogenesis and prevention of AMD.