Intraocular Pressure Lowering, Change of Antiapoptotic Molecule Expression, and Neuroretinal Changes by Dorzolamide 2%/Timolol 0.5% Combination in a Chronic Ocular Hypertension Rat Model

The aim of this study was to examine intraocular pressure lowering, change of antiapoptotic molecules expression, and neuroretinal changes by a commercially available dorzolamide 2%/timolol 0.5% combination in a chronic ocular hypertension rat model. Chronic ocular hypertension was induced by three episcleral vein cauterizations. The expression of antiapoptotic molecules and the effect of dorzolamide 2%/timolol 0.5% combination in chronic ocular hypertensive retina were evaluated. Retinal ganglion cell (RGC) retrograde labeling and quantification with 4-di-10-ASP (DiA) and expression of glial fibrillary acidic protein (GFAP) were detected before and after the administration of dorzolamide 2%/timolol 0.5%. Treatment of ocular hypertensive eyes with dorzolamide 2%/timolol 0.5% significantly reduced, intraocular pressure when compared to the control eyes. Labeling of RGCs with DiA showed a significant decrease in RGC loss after the administration of dorzolamide 2%/timolol 0.5%. GFAP expression revealed a significant decrease in retinal damage after dorzolamide 2%/timolol 0.5% administration. However, dorzolamide 2%/timolol 0.5% did not affect Bcl-2 and Bcl-xL mRNA expression. In conclusion, dorzolamide 2%/timolol 0.5% may have neuroprotective potential in the animal model, which is not mediated by Bcl-2 or Bcl-xL. The mechanism of neuroprotection by dorzolamide 2%/timolol 0.5% in chronic glaucoma models requires further investigation.