Effect Of Dihydromyricetin Isolated From Ampelosis Grossedentata On Wet Age-related Macular Degeneration

Object: The feasibility of wet age-related macular degeneration(AMD) induced by laser in Japanese white rabbits was evaluated. The effect of dihydromyticetin, isolated from ampelosis grossedentata on wet age-related macular degeneration, was explored.Methods: AMD models were structured by 532 nm laser photocoagulation to the retina of adult Japanese big ear white rabbits. Four to twelve weeks later after light coagulation, rabbits were anesthetized. Then fundus fluorescein angiography(FFA) and optical coherence tomography(OCT) for light condensing zone were made. And enzyme linked immunosorbent assay(ELISA) was employed to detect the expression levels of rabbit peripheral blood vascular endothelial growth factor(VEGF). After intragastric administration(100 mg DMY ?kg-1?d-1), VEGF and PEDF levels both in peripheral blood and aqueous humor were analyzed by ELISA; the expression levels of VEGF and PEDF mRNA were detected by real-time fluorescence quantitative PCR(Real-time PCR); HE staining was used to detected the CNV, and the experimental animal were dissected to calculate the liver, kidney and spleen index at the end of the experiment.Results: After 4-12 weeks photocoagulation, FFA showed the punctuate fluorescence in the laser parts of macular retinal, and OCT image displayed the fracture of retinal pigment epithelial layer. The VEGF levels in peripheral blood were elevated to some extend.After administration for 4 weeks, VEGF level of peripheral blood in model group decreased by 63.3%, while the model control group reduced by 48.6%. After administration for 8 weeks, VEGF level of peripheral blood in model group decreased by 46.7%, while the model control group reduced by 20.1%. The VEGF concentration of aqueous humor in model group was 2271.4 ng/L after administration for 8 weeks, while it was 2967.5 ng/L in the model control group. After administration for 4 weeks, PEDF level of peripheral blood in model group decreased by 55.9%, while the model control group reduced by 58.6%. After administration for 8 weeks, PEDF level of peripheral blood in model group decreased by 12.1%, while the model control group reduced by 53.1%. The PEDF concentration of aqueous humor in model group was 195.1μg/L after administration for 8 weeks, while it was 153.3μg/L in the model control group.After administration for 8 weeks,the expression level of VEGF mRNA in model group was significantly lower than that of the model control group(P < 0.01), and the expression level were 0.5 times and 13.9 times of the normal control, respectively. After administration for 8 weeks,the expression level of PEDF mRNA in model group was significantly lower than that of the model control group(P < 0.01), and the expression level were 1.7 times and 4.8 times of the normal control, respectively.After administration for 8 weeks,CNV was visible in model control group, while it had no obvious CNV in the model administration group. The liver index and spleen index in model group were significantly lower than that of the model control group(the P value was 0.147 and 0.223 respectively), while the kidney index had no significant difference(P=0.874).Conclusion: After 532 nm laser coagulation(power with 900 mW, 0.1s), Japanese white rabbit fundus can effectively induce the formation of corneal neovascularization(CNV), the development of vascular leakage, the establishment successfully of wet AMD model.Treated by DMY, the down-regulation of VEGF protein and VEGF mRNA expression level had the same trend; while the up-regulation of PEDF protein expression level was not uniform with the down-regulation of PEDF mRNA expression level.DMY exhibited a certain inhibition effect on the CNV growth of wet AMD rabbits, and it’s mechanism may be related to the down-regulation of VEGF level, the upregulation of PEDF level, promotion blood flow and invigoration spleen and soothing liver.