Effects of retina on macromolecules diffusion after retinal vein occlusion
- VernacularTitle:视网膜静脉阻塞后视网膜对大分子物质通透性的影响
- Author:
Yong TAO
;
Xiaoxin LI
;
Yanrong JIANG
- Publication Type:Journal Article
- Keywords:
Retinal vein occlusion/drug therapy;
Permeability/drug effects;
Macromolecular substances/pharmacokinetics;
Disease models,animal
- From:
Chinese Journal of Ocular Fundus Diseases
2008;24(3):197-201
- CountryChina
- Language:Chinese
-
Abstract:
Objective To observe the change of diffusion upper limit of macromolecules through pathological retina and the difference between the layers of retina. Methods Retinal edema was emulated by establishing branch retinal vein occlusion(RVO)model in miniature pig eyes under photodynamic method.Two days later,the retinas of both eyeballs were peeled off.The diffusion test apparatus was designed by ourselves.FITC-dextrans of various molecular weights(4.4,9.3,19.6,38.9,71.2 and 150 kDa)and Carboxyfluorescein(376 Da)were dissolved in RPMI-1640 solutions and diffused through inner or outer surface of retina.The rate of transretinal diffusion was determined with a spectrophotometer.Theoretical maximum size of molecule(MSM)was calculated by extrapolating the trend-linear relationship with the diffusion rate.In separate experiments to determine the sites of barrier tO diffusion,FITC-dextrans were applied to either the inner or outer retinal surface,processed as frozen sections.and viewed with a fluorescence microscope. Results FITC-dextrans applying tO inner retinal surface,4.4 kDa dextrans were largely blocked by inner nuclear layer(INL);19.6-71.2 kDa dextrans were blocked by the nerve fiber layer(NFL)and inner plexiform layer;150 kDa dextrans were blocked by NFL.FITC-dextrans applying to outer retinal surface,most dextrans with various molecular weights were blocked before outer nuclear layer(ONL).No matter applying to the inner or outer surface,Carboxyfluorescein can diffuse through the whole retina and aggregate at INL and ONL.After RVO,the inner part of retina became edema and cystoid,loosing the barrier function.Compared with the normal retina,the MSM in RVO tissues increased(6.5±0.39nm Vs 6.18±0.54nm,t=4.143,P=0.0001). Conclusions After RVO,the barrier function of inner part of retinal is destroyed and the upper limit of diffusion macromolecule size increased.which is nevertheless limited.ONL acts as bottle-neck barriers to diffusion,if the outer part of retina is damaged,the change of the diffusion upper limit will be prominent.
