Effects of antifungal drugs and delivery vehicles on morphology and proliferation of equine corneal keratocytes in vitro.

This study explored the impact of different antifungal drugs and delivery methods on the growth and physical characteristics of horse cells that produce a transparent layer on the front of the eye, called keratocytes.

Research Context

• This research was carried out on the corneal cells or ‘keratocytes’ of horses. The overall aim of the study was to determine any effects of topical antifungal drugs and their delivery vehicles on the characteristics and growth rate of these keratocytes.

Methods

• The study was performed using primary cultures of keratocytes procured from the corneal stroma of 16 horse corneas, collected post-euthanasia.
• The researchers exposed these keratocytes to varying concentrations of three commonly used antifungal drugs: natamycin, itraconazole, and miconazole. The cells were also exposed to the drug delivery vehicles DMSO, benzalkonium chloride, carboxymethylcellulose, and a combination of polyethylene glycol, methylparaben, and propylparaben.
• To assess the impact of these drugs and delivery vehicles, the researchers observed any changes in cell morphology and proliferation rates 24, 48, and 72 hours after application.

Findings

• At their highest tested concentrations, all of the antifungal drugs resulted in significant changes to cell morphology and inhibited cell growth.
• Natamycin and miconazole, at low concentrations, caused the cells to round off, shrink, and detach, indicative of inhibited cellular proliferation.
• Of the antifungals studied, natamycin caused the most severe changes in cell morphology.
• Itraconazole, on the other hand, brought about minimal changes in cell morphology and had a minimal effect on cell growth, even at low concentrations.
• Compared to the tested antifungals, all of the drug delivery vehicles had significantly less impact on cell morphology and growth rate. The only exception was the combination vehicle consisting of polyethylene glycol, methylparaben, and propylparaben which, even at low concentrations, caused severe morphological changes and inhibited growth.
• DMSO, a standard solvent for biological studies, had minimal effects on cellular morphology and proliferation, even at high concentrations.

Conclusions

• Based on in vitro tests, itraconazole had significantly less cytotoxic effects on horse keratocytes compared to natamycin or miconazole. The study also highlighted the severe cytotoxic effects associated with natamycin.