The influence of antiglaucoma drugs and its components on cultured human corneal endothelial cells

Purpose. Evaluation of cytotoxicity of antiglaucoma drugs and preservative – benzalkonium chloride (BAK) in human corneal endothelial cells (CECs) in vitro. Material and methods. High-CEC-density colonies were used as a monolayer (intact endothelium in vivo) and single CECs were regarded as low-HCEC-density layer in bullous keratopathy. Dorzolamide, brimonidine, timolol (preserved and BAK-free) were diluted with medium up to 1/10000, 1/1000, 1/100. BAK was diluted according to its concentration in these solutions. Following exposure to test solutions for 24 hours, morphological features of both CEC-models were identified with phase-contrast microscope, CECs survival was measured using MTS assay. Results. Dorzolamide and Timolol, preservative-free, 1/1000 and 1/100 dilutions, induced structural changes of single CECs. Timolol, preservative-free, 1/1000 and 1/100 dilutions, caused changes of CEC-monolayer. Dorzolamide, brimonidine and timolol (preservative-free, 1/100 dilutions) have not caused the decline of CEC viability in both models. Dorzolamide, preserved, 1/100 dilution, was toxic to CEC-monolayer. Brimonidine and timolol (preserved, 1/100 dilutions) induced CECs'death in monolayer. Low single CECs viability (29%) was detected after exposure to Dorzolamide, preserved, 1/100 dilution. High cytotoxicity of brimonidine and timolol (both preserved, 1/100 dilutions) to CEC-monolayer was confirmed by MTS-test – 25% and 3%, respectively and to single CECs – 23,4% and 4,2%, respectively. BAK showed similar level of CECs'toxicity as preserved drugs. So, the cytotoxicity of these drugs was induced by BAK as a component. Conclusions. High concentrations of preserved antiglaucoma ophthalmic solutions may disturb CECs. Administration of such drugs is not reasonable in eyes with low corneal endothelial cell density. Keywords: dorzolamide, brimonidine, timolol, benzalkonium chloride, corneal endothelium, cytotoxicity