Purpose: Long-term use of topical medication is needed for glaucoma treatment. One of the most commonly prescribedclasses of hypotensive agents are prostaglandin analogs (PGs) used as both first-line monotherapy; aswell as in combination therapy with other hypotensive agents. Several side effects of eye drops can be caused bypreservatives. The purpose of this study was to evaluate the effects of PGs with varying concentrations of benzalkoniumchloride (BAC), alternative preservatives, or no preservatives on human conjunctival fibroblast cells.
Methods: Primary human conjunctival fibroblast cells were used in these experiments. Cells were exposed to the followingdrugs: BAC at different concentrations, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC0.02%), tafluprost 0.0015% with/without 0.001% BAC and travoprost 0.004% (with 0.001% Polyquad) for 15 and 30minutes. Cell cytotoxicity was evaluated by phase-contrast microscopy to monitor morphological changes of cells,Counting Kit-8 (CCK-8) assay to cell viability, and fluorescent activated cell sorting (FACS) analysis to measureapoptosis.
Results: BAC caused cell shrinkage and detachment from the plate in a dose-dependent manner. Morphologicalchanges were observed in cells treated with bimatoprost 0.01% and latanoprost 0.005%. However, mild cell shrinkagewas noted in cells treated with tafluprost 0.0015%, while a non-toxic effect was noted with travoprost 0.004%and preservative-free tafluprost 0.0015%. CCK-8 assay and FACS analysis showed all groups had a significantlydecreased cell viability and higher apoptosis rate compared with the control group. However, travoprost 0.004%and preservative-free tafluprost 0.0015% showed lower cytotoxicity and apoptosis rate than other drugs.
Conclusions: This in vitro study revealed that BAC-induced cytotoxicity is dose-dependent, although it is importantto emphasize that the clinical significance of toxicity differences observed among the different PGs formulationshas not yet been firmly established. Alternatively preserved or preservative-free glaucoma medications seem to bea reasonable and viable alternative to those preserved with BAC.