Comparison of cytotoxicities and antiallergic effects of topical ocular dual-action anti-allergic agents

Abstract

Background: To investigate the cytotoxicities of the topical ocular dual-action anti-allergic agents (alcaftadine 0.25%, bepotastine besilate 1.5%, and olopatadine HCL 0.1%) on human corneal epithelial cells (HCECs) and their anti-allergic effects on cultured conjunctival epithelial cells. Methods: A Methylthiazolyltetrazolium(MTT)-based calorimetric assay was used to assess cytotoxicities using HCECs at concentrations of 10, 20 or 30% for exposure durations of 30 min, 1 h, 2 h, 12 h or 24 h. Cellular morphologies were evaluated by inverted phase-contrast and electron microscopy. Wound widths were measured 2 h, 18 h, or 24 h after confluent HCECs monolayers were scratched. Realtime PCR was used to quantify anti-allergic effects on cultured human conjunctival cells, in which allergic reactions were induced by treating them with Aspergillus antigen. Results: Cell viabilities decreased in time- and concentration-dependent manners. Cells were detached from dishes and showed microvilli loss, cytoplasmic vacuoles, and nuclear condensation when exposed to antiallergic agents; alcaftadine was found to be least cytotoxic. Alcaftadine treated HCECs monolayers showed the best wound healing followed by bepotastine and olopatadine (p < 0.0001). All agents significantly reduced the gene expressions of allergic cytokines (IL-5, IL-25, eotaxin, thymus and activation-regulated chemokine, and thymic stromal lymphopoietin) and alcaftadine had the greatest effect (p < 0.0001 in all cases). Conclusions: Alcaftadine seems to have less side effects and better therapeutic effects than the other two antiallergic agents tested. It may be more beneficial to use less toxic agents for patients with ocular surface risk factors or presumed symptoms of toxicity.