The Evaluation Of Toxicity Of Antiglaucoma Drugs And Its Components To Cultured Human Corneal Endothelial Cells

To evaluate the toxicity of antiglaucoma ophthalmic solutions in the presence and absence of preservative - benzalkonium chloride (BAK) to human corneal endothelial cells (HCEC) using in vitro techniques.

Federal State Budgetary Institution of Science “M.M. Krasnov Research Institute of Eye Diseases”, Moscow, Russia (119021, Moscow, Rossolimo st., 11 A, B)

Primary cultures of HCEC were derived from eye bank specimens to create two in vitro experimental models: intact endothelium (HCEC-monolayer) and endothelial cell dysfunction as a cause of bullous keratopathy (low-HCEC-density layer). Brimonidine, Dorzolamide, Timolol in the presence (preserved, P) and absence (preservative-free, P-F) of BAK were each diluted with growth medium to make dilutions of 1/10000, 1/1000, 1/100. BAK was diluted according to its concentration in the test solutions of antiglaucoma drugs. HCEC survival was measured following exposure of low-HCEC-density layer to these solution dilutions for 24 hours using MTS assay. Morphological features of both HCEC-models were identified with phase-contrast microscope.

Dorzolamide and Timolol, both P-F, 1/1000 and 1/100 dilutions, induced structural changes of low-HCEC-density layer. Timolol, P-F, 1/1000 and 1/100 dilutions, caused changes of HCEC-monolayer. Dorzolamide and Timolol, both P, 1/1000 dilutions, produced toxicity to low-HCEC-density layer. Dorzolamide, P, 1/100 dilution, was toxic to HCEC-monolayer and low-HCEC-density layer (viability reduction by 21.4%). Timolol, P, 1/100 dilution, induced HCECs’ death in monolayer and low-HCEC-density layer (reduction by 79%). Brimonidine, P, 1/100 dilution, caused apoptosis in HCEC-monolayer and low-HCEC-density layer (reduction by 68.8%). BAK (diluted up to its concentration in test solutions) showed similar level of HCECs’ toxicity as preserved drugs.

Preserved antiglaucoma ophthalmic solutions may disturb the structure and functions of HCEC. Thereby, administration of preserved intraocular pressure lowering drugs is not reasonable in eyes with corneal endothelial cell dysfunction (bullous keratopathy, Fuchs endothelial corneal dystrophy, etc.) or after keratoplasty.