Protective Effect of Topical 5-S-GAD on UV-B -Induced Cataract in Rats

Abstract

Purpose: : 5-S-GAD is a novel antibacterial substance purified from Sarcophaga peregrina (Flesh Fly) by Natori et al., in 1994. Its properties include radical scavenging and anti-oxidative activities. We investigated the protective effect of topical 5-S-GAD on UV-B-induced cataract in rats.

Methods: : Brown Norway male rats (N=32, 6-weeks years old) were treated with either 5-S-GAD (0.1% or 1%) eye drops or astaxanthin 0.1% suspension eye drop or the vehicle alone (the solution without 5-S-GAD) 3 times a day (3 times with two 5 min intervals). The treatment was given 2 days before UV-B exposure and 2 days after UV-B exposure. Each rats received UV-B exposure of 100-200 mJ/cm² totaling 1,200 mJ/cm². Light scattering intensity (LSI) of the anterior subcapsular and nuclear layers were measured and cataracts were documented by Scheimpflug system (EAS-1000, NIDEK) under mydriasis.Ocular penetration of 5-S-GAD was analyzed using high-pressure liquid chromatography.

Results: : 8 and 9 weeks following initial UV-B exposure, LSI of the anterior subcapsular layers of the 5-S-GAD (0.1% and 1%) treated groups were significantly lower than those of the vehicles. On the other hand, no significant difference was found for the AST treated group. No significant difference was found for nuclear lenses. 5-S-GAD in the aqueous humor was detected.

Conclusions: : 5-S-GAD penetrates into the aqueous humor following topical administration and has the potential to delay the progression of UV-B-induced cataract in rats.

Keywords: cataract • radiation damage: light/UV • aqueous