Effect of preservative-free and preserved prostaglandin analogues on the histology of cornea of adult male Guinea pigs following repeated exposure.

Abstract

Glaucoma is a group of eye diseases that can cause vision loss. Prostaglandin analogues (PGAs) are known to be the first line for treatment of patients with glaucoma. Latanoprost is a good, efficient & tolerated PGA that currently available as latanoprost with Benzalkonium chloride (BAC) (Xalatan) and preservative-free (PF) prostaglandins analogue latanoprost (Monopost). Lately, utilizing of PF anti-glaucoma agents is considered an essential procedure for enhancing glaucoma care. This study aims to analyze the histological changes within the corneal tissue with the use of currently available preserved prostaglandins (PG) - derived eye drops, and PF prostaglandins analogue. In this study, forty male guinea pigs were distributed into four equal groups. Control group, Latanoprost with 0.02% BAC treated group, Recovery group and PF Latanoprost treated group. After two months, the corneal tissues of guinea pigs were prepared for light and electron microscopic studies, morphometric and statistical studies were performed. Our results indicate that guinea pigs treated with latanoprost with BAC exhibited ocular surface changes, there was epithelial thinning with desquamation, the stroma showed irregularly arranged collagen fibers and small keratocytes. Morphometrically, there was a marked decrease in the thickness of epithelium and number of keratocytes. Negative PAS reaction was observed in some parts of the epithelial basement membrane. The epithelium gives a strong positive immunoreactivity for Bax. Guinea pigs left to recover exhibited improvement, while treatment of animals with PF latanoprost revealed nearly normal corneal structure. In conclusion, PF prostaglandin anti-glaucoma medication seems to be better and protective on cornea of male guinea pigs than prostaglandins with BAC preservative.