Experimental study on intraocular posterior capsule opacification in intraocular lens treated by rapamycin / 中华实验眼科杂志

ABSTRACT

Background Posterior capsule opacification (PCO) is a main cause for visual acuity decline after modern extracapsular cataract surgery.Objective The aim of this study was to investigate the effect of rapamycin on PCO formation following phacoemulsification combined with intraocular lens (IOL) implantation in rabbit eyes.Methods Thirty New Zealand albino rabbits were randomized into three groups according to the difference in the implanted IOLsconventional IOL without modification,IOL coated by a polymer material and IOL with sustained released rapamycin.Phacoemulsification combined with intraocular lens implantation surgery was performed in the left eye.The anterior ocular segment and PCO formation in the rabbit eyes were examined by slit lamp biomicroscope 1-7 days after operation,and the flare and inflammatory response of the anterior chamber as well as the degree of PCO severity were graded based on the criteria of Yang.The differences in examination outcomes were compared by the Kruskal-Wallis H test.The animals were sacrificed 12 days after surgery and eye specimens were prepared for histopathological examination to evaluate the biological behavior of lens epithelial cells (LECs) on the posterior capsule.Results The coated area of the implanted lens was semi-transparent with a smooth surface.The number of eyes with aqueous flare at grades 3 and 4 insignificantly increased but those with an inflammatory response at grades 3 and 4 significantly increased in the conventional IOL group and the polymer modified IOL group,compared with the rapamycin modified IOL group on the first day after operation (H =4.038,P =0.133 ; H =8.604,P =0.014).On the seventh day,the number of eyes with aqueous flare at grades 3 and 4 and inflammatory response at grades 3 and 4 significantly increased in the conventional IOL group and the polymer modified IOL group,compared with the rapamycin modified IOL group (H =8.891,P =0.012 ; H =7.664,P =0.0220).The histopathological examination showed that marked proliferation of LECs appeared between the anterior and posterior capsule in the conventional IOL group and the polymer modified IOL group;however,less LECs and regenerative cortex were seen in the rapamycin modified IOL group.Conclusions IOL loaded with rapamycin can inhibit the inflammatory response and alleviate the severity of PCO after phacoemulsification combined with IOL implantation.The implantation of IOL loaded with rapamycin may be a new approach to the prevention and treatment of PCO.