Study On The Effect Of Astragaloside ? Nanoemulsion Gel On Experimental Dry Age-related Macular Degeneration Rat Model

ObjectiveTo observe the effect of Astragaloside IV nanoemulsion gel on experimental dry age-related macular degeneration rat model and to explore its mechanism.This provides new methods and new ideas for the treatment of dry AMD.Methods1.Protective effect of Astragaloside IV nanoemulsion gel on experimental dry AMD rat model:The model was induced by tail vein injection of sodium iodate.The model rats were randomly divided into 3 groups with 15 mice in each group:model control group,Astragaloside IV nanoemulsion gel group,Esculin and Digitalisglycosides eye drops group.The medicines were given on the first day after modeling and 4 times a day.The medicines were given at 9:00,12:00,15:00 and 18:00 respectively.No special treatment is given to the normal group.After 14 days,electroretinograms and histopathological changes of the retina were observed.2.Effects of Astragaloside IV nanoemulsion gel on apoptosis of retinal cells in experimental dry AMD rats:modeling,grouping and administration methods were the same as the above.After 14 days,the apoptosis of retinal cells was detected by TUNEL,and the oxidative damage of mtDNA was detected by immunofluorescence.3.Effects of Astragaloside IV nanoemulsion gel on the expression of Keap1-Nrf2/ARE signaling pathway:modeling,grouping and administration methods were the same as the above.After 14 days,relative expression levels of Keap1,Nrf2,HO-1,and NQO1 mRNA in the retina tissue were measured by Reverse Transcription PCR.Results1.ERG:After 14 days,the ERG indexes in the model control group were significantly lower than those in the normal group(P<0.05).ERG indicators in the treatment groups were significantly improved compared with the model control group(P<0.05).In Scotopic 0.01 ERG and Scotopic 3.0 ERG,there was no significant difference between the Astragaloside IV nanoemulsion gel group and the Esculin and Digitalisglycosides eye drops group(P>0.05).In Scotopic 3.0 oscillatory potentials,the total amplitude of ERG in the group of Esculin and Digitalisglycosides eye drops was higher than the Astragaloside ? nanoemulsion gel group(P<0.05).In Photopic 3.0 ERG and Photopic 3.0 flicker,the amplitude of ERG b wave of Astragaloside ?nanoemulsion gel group was higher than the Esculin and Digitalisglycosides eye drops group(P<0.05).2.Histopathological:After 14 days,the RPE layer and ONL of the model control group had obvious pathological lesions.The number of cells was decreased and the ONL was changed with the wave sample.Compared with normal group,the difference was statistically significant(P<0.05).Compared with model control group,the degree of retinopathy in the treatment groups were improved(P<0.05).The number of RPE layers and ONL cells in the astragaloside nanopigment gel group was greater than that of the Esculin and Digitalisglycosides eye drops group(P<0.05).3.TUNEL:After 14 days,the model control group had a large number of apoptotic cells.Apoptotic cells were uniformly constricted or crescent shaped.Compared with normal group,the difference was statistically significant(P<0.05).Compared with the model control group,the apoptotic cells were significantly decreased in the treatment groups(P<0.05).The apoptotic rate of retinal cells in the Astragaloside IV nanoemulsion gel group was lower than the Esculin and Digitalisglycosides eye drops group(P<0.05).4.Immunofluorescence:After 14 days,the RPE layer,ONL and INL in the model control group were all positive expressions of 8-OHdG.Compared with normal group,the difference was statistically significant(P<0.05).Compared with model control group,the 8-OHdG positive expressions were significantly reduced in the treatment groups(P<0.05).The DNA damage rate of RPE cells in Astragaloside IV nanoemulsion gel group was lower than that of the Esculin and Digitalisglycosides eye drops group(P<0.05).5.RT-PCR:After 14 days,the relative expression of Keapl mRNA in the retina of model control rats was significantly increased.Compared with normal group,the difference was statistically significant(P<0.05).Compared with the model control group,the relative expression of Keapl mRNA was decreased in the treatment group(P<0.05).The relative expression levels of Nrf2,HO-1 and NQO1 mRNA were significantly reduced in the model control group.Compared with normal group,the difference was statistically significant(P<0.05).Compared with model control group,the relative expression levels of Nrf2,HO-1 and NQO1 mRNA were increased in the treatment groups(P<0.05).The relative expression of HO-1 mRNA in the Astragaloside IV nanoemulsion gel group was higher than that of in the Esculin and Digitalisglycosides eye drops group(P<0.05).There was no significant difference in the relative expression of other factors between the two groups(P>0.05).Conclusion1.Astragaloside IV nanoemulsion gel has protective effects on experimental dry AMD rats.It can improve retinal cells function and reduce pathological tissue damage.2.Astragaloside IV nanoemulsion gel can inhibit retinal cells apoptosis and repair mtDNA damage in experimental dry AMD rats.3.The mechanism of Astragaloside IV nanoemulsion gel for protecting the retina of experimental dry AMD rats may be related to the regulation of Keapl-Nrf2/ARE signaling pathway.