Changes of the Retina and Intrinsic Survival Signals in a Rat Model of Glaucoma following Brinzolamide and Travoprost Treatments.

Purpose: The purpose of this study is to examine the changes of the retina and the intrinsic survival signals of the retina by brinzolamide (Azopt®) and travoprost (Travatan®) in a rat model of chronic ocular hypertension.

Methods: Chronic ocular hypertension was induced by cauterization of three episcleral veins. Terminal deoxynucleotidyl transferase-mediated dUTP-nick end-labeling (TUNEL) staining was performed and the expression of glial fibrillary acidic protein (GFAP) was examined to evaluate changes of retinal ganglion cell (RGC) apoptosis and glial cell activation. Western blot analyses of the bcl-2 family and extracellular signal-regulated kinases (ERK) were done to identify changes of the intrinsic survival signaling pathway in the retina.

Results: GFAP expression and TUNEL staining revealed significant decreases in RGC apoptosis and glial cell activation after brinzolamide and travoprost administration; bcl-2 and bcl-xL expression were significantly increased after intraocular pressure elevation and it was further increased with brinzolamide and travoprost treatment. This enhancement of survival signaling may have contributed to the decrease in RGC apoptosis. However, the role of ERK signaling was not significant.

Conclusions: Decrease in retinal damage and increased intrinsic survival signals suggests the neuroprotective potential of brinzolamide and travoprost in an animal model of chronic ocular hypertension, but further studies are required.