An Alternative Method of Steroid-Induced Lens Opacification in Brown Norway Rat Eyes Applying Systemic Pulse Administration

Abstract

Purpose: To confirm whether long-term administration of prednisolone sodium succinate (prednisolone) alone is able to induce cataract in rat eyes. Materials and Methods: A 1% solution of prednisolone was administered topically as eye drops to Brown Norway rat eyes, and a systemic pulse administration of 10 mg/kg/day was given via the tail vein. Both administration methods were applied in different combinations. Eighty-three 6-week-old male rats were divided into 8 groups: group 1 = control; group 2 = topical instillation every day; group 3 = single pulse; group 4 = single pulse + eye drops; group 5 = 3 times pulse; group 6 = 3 times pulse + eye drops; group 7 = 3 times pulse per 2 months; group 8 = 3 times pulse per 2 months + eye drops. Observations for changes of lens transparency were made by slitlamp microscopy and documented by an anterior eye segment analysis system (Nidek EAS-1000^®) from the onset of drug administration to a maximum period of 16 months. Results: Lens opacity in the shallow anterior and posterior lens layers developed from the tenth month following commencement of prednisolone administration. The incidence of anterior and/or posterior cortical cataract at the sixteenth month was 15% in group 2, 12.5% in group 5, 25% in group 6, 17.9% in group 7 and 35.3% in group 8. The lenses of groups 1, 3 and 4 maintained their transparency throughout the observation period. Light scattering intensity in groups 8 and 7 was the highest, followed by groups 6 and 5, then groups 2, 4, 3 and 1. Conclusion: Cortical cataract was successfully induced in Brown Norway rat eyes by sustained administration of prednisolone succinate alone applied as systemic pulse.