Exploring The Efficacy And Mechanism Of Taxifolin On Blue Light Induced Dry Age-related Macular Degeneration Model

Objective:We established a rat model of dry age-related macular degeneration BN by optimizing the blue light exposure modeling method,and initially explored the protective effect and the mechanism pathway of taxifolin on retinal degeneration in BN rats,providing new ideas for the treatment of dry macular degeneration.Methods:Retinal atrophy was induced in BN rats by the anesthesia-dilated blue light illumination method and the bright-dark cycle blue light illumination method.The advantages and disadvantages of the two models were evaluated,and an optimized model of dry age-related macular degeneration was established.Control group,model group,low-dose group and high-dose group were established,and taxifolin was given for 28 days.Retinal functional status was detected by retinal electrophysiology(ERG),retinal structural morphology by optical coherence tomography(OCT);We used slit lamp microscopy,fundus imaging,histopathological examination,Td T-mediated d UTP Nick-End Labeling(TUNEL),enzyme-linked immunosorbent assay(ELISA)for modeling and efficacy evaluation;The mechanism of taxifolin were further explored by detecting target proteins and related genes by Western-Blot,PCR and other methods.Result:Exposure to blue light at 440-450 nm under anesthesia for 1 h/ day and 12 light /12 dark cycles at 440-450 nm can lead to retinal damage in BN rats,and establish a dry macular degeneration model,showing retinal hyperreflectivity,decreased ERG a-wave and b-wave amplitudes,and reduced retinal thickness similar to clinical dry macular degeneration.degeneration can be used to establish a model of dry macular degeneration.The former model of dry macular degeneration is likely to cause inflammation in the anterior segment of experimental animals,and repeated anesthesia may lead to animal death,which ultimately affects the success rate of the model,The latter one can be established under 3 days of blue light exposure with a 100% success rate,without anesthetic dilatation,and the model can be maintained for at least 28 days.Moreover,there is no significant inflammatory response in the anterior segment of the eye.The refractive media is clear and intact.Compared with the control group,BN rats given 10 mg/kg taxifolin and 50 mg /kg taxifolin showed protective effects on retina 14 and 28 days after administration,including increased ERG amplitude,improved visual function and reduced retinal thickness.It delayed retinal atrophy,maintained retinal tissue structure,reduced the number of apoptosis in retinal cells,reduced the production of toxic metabolites in retinal tissue,and enhanced antioxidant activities of SOD and GSH-Px.The difference was statistically significant.The protective effect of 50 mg/kg taxifolin was better than 10 mg/kg.The results of the passageway study showed that the protein and m RNA expression of NRF2,HO-1,NQO-1,GCLC,and GLCM were up-regulated in the retinal tissues of rats at two different doses after 28 days of administration,but the up-regulation of gene expression was not significant in the low-dose group,while most of the data were statistically significant in the high-dose group.Conclusions:(1)Blue light at 440--450 nm wavelength has high modeling efficiency.Both anesthesia-dilated blue light illumination method and the bright-dark cycle blue light illumination method can damage the retina of rats,and the dry age-related macular degeneration model is established successfully.The former is easy to damage the anterior segment,has high animal mortality and low model success rate,but this method is more consistent with human injury mechanism and is suitable for mechanism or pathway research;the latter model is stable and has high success rate,and can observe retinal structural and functional changes at various stages of drug administration,which is suitable for non-clinical drug evaluation.Light intensity of 1000 Lux can reduce the stress response of experimental animals and is more suitable for model building.(2)Taxifolin(dose ≥10 mg/kg)has a certain retinal protective effect,and dose ≥50mg/kg can show obvious antioxidant effects,including improving animal visual function,delaying retinal atrophy,reducing the number of retinal cell apoptosis,reducing the production of toxic metabolite MDA in retinal tissue,improving the activity of SOD,GSH-Px and other antioxidant enzymes.(3)The up-regulation of NRF2 and the enhancement of phase II antioxidant enzyme system may be one of the mechanisms by which taxifolin protects retina from oxidative stress.