RESUMO
Background Many eye diseases such as central retinal artery occlusion,glaucoma and ischemic optic neuropathy,etc.lead to retinal ischemia-reperfusion injury (RIRI) and furthmore visual functional damage.It is neeessary to study the treatment of RIRI.Objective This study was to observe and discuss the influence of aminoguanidine on the retina morphological changes and its mechanism after RIRI.Methods Eighty clean healthy male Japanese white rabbits were randomly divided into normal injury group,RIRI group and aminoguanidine (AG)treated group.The model of RIRI was established by infusing saline solution into the anterior chamber to elevate intraocular pressure (IOP) in both RIRI group and AG group.AG was intraperitoneally injected in the models of the AG group,and normal saline solution was used at the same method in tbe normal group and the RIRI group.The fundus photography and fundus fluorescein angiography(FFA) were pertormed on the rabbits at the moment of retina ischemia and 6,24 and 72 hours after reperfusion.The parts of rabbits were sacrificed 1,6,24 and 72 hours after reperfusion,followed by the enucleation of the eyeballs.Retinal section was prepared for TUNEL examination to evaluate the apoptosis of retinal cells.Nitric oxide (NO) concentration in retina was detected with nitrate reductase,and the activity of inducible nitric oxide synthase (iNOS) was measured by colorimetric detection.The use of the animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results The fundus photography and FFA showed that the retinal edema was more mild,and the percentage of vascular occlusion was lower in the AG treatment group than that in RIRI group and the amount and area of fluorescein leakage were also smaller than the treatment group.The numbers of TUNEL positive cells in the AG treatment group were less than those in the RIRI model group at 1,6,24 and 72 hours after experiment (F分组 =2762.37,P =0.00 ; F时间 =894.24,P =0.00).Numbers of TUNEL positive cells between adjacent time points were significantly different in both RIRI model group and AG treatment group (RIRI group:q =24.475,36.591,-20.37,P＜0.05;AG group:q =20.94,16.79,-6.92,P＜0.05),with the peak value at 24 hours after experiment.NO contents were significantly higher in the RIRI model group compared to AG group at various time points(q =3.84,4.01,8.91,3.75,P＜0.05),and those between adjacent time points showed significant differences (RIRI group:q=4.77,13.403,-10.29,P＜0.05;AG group:q=4.55,9.05,-5.08,P＜0.05).iNOS activity was significantly elevated in the RIRI model group compared with AG group(q=-3.74,-4.94,-6.53,-3.98,P＜0.05),and obvious differences also were seen between the adjacent time points in both two groups(RIRI group:q =8.43,6.71,-6.39,P＜0.05 ;AG group:q =4.16,5.08,-3.93,P＜0.05).Conclusions Aminoguanidine can protect the retinal function and morpbology from oxidative stress damage after RIRI by reducing the NO level and inhibiting the iNOS activity in retina.