Effects of antifungal drugs and delivery vehicles on morphology and proliferation of equine corneal keratocytes in vitro.
OBJECTIVE
To evaluate the effects of topical antifungal drugs and delivery vehicles on the morphology and proliferation rate of cultured equine keratocytes.


METHODS
16 corneas obtained from 8 apparently ophthalmologically normal horses < 0.5 hours after euthanasia for reasons unrelated to the study.


METHODS
Primary cultures of equine keratocytes were obtained from corneal stroma and were exposed to several concentrations of 3 commonly used, topically applied antifungals: natamycin, itraconazole, and miconazole. In addition, effects of drug delivery vehicles DMSO, benzalkonium chloride, and carboxymethylcellulose and a combination vehicle composed of polyethylene glycol, methylparaben, and propylparaben were also evaluated. Morphological changes and cellular proliferation were assessed 24, 48, and 72 hours after application.


RESULTS
At the highest concentrations tested, all antifungals caused marked cellular morphological changes and inhibited proliferation. At low concentrations, natamycin and miconazole induced rounding, shrinking, and detaching of the cells with inhibition of cellular proliferation. Natamycin caused the most severe cellular changes. Itraconazole, at the low concentrations, caused minimal morphological changes and had a minimal effect on proliferation. All vehicles tested had significantly less effects on cellular morphology and proliferation when compared with the antifungals, except for the combination vehicle, which caused severe morphological changes and inhibited proliferation, even at low concentrations. The DMSO had minimal effects on cellular morphology and proliferation, even at high concentrations.


CONCLUSIONS
Itraconazole had significantly less cytotoxic effects on equine keratocytes in culture than did natamycin or miconazole. Natamycin had severe cytotoxic effects in vitro.
Mathes
Rachel L
RL
Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA. rmathes@uga.edu
Reber
Adrian J
AJ
Hurley
David J
DJ
Dietrich
Ursula M
UM
D000818:Animals; D000935:Antifungal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001548:Benzalkonium Compounds / Q000494:pharmacology; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects*; D003315:Cornea / Q000166:cytology* / Q000187:drug effects; D003319:Corneal Stroma / Q000166:cytology* / Q000187:drug effects; D006736:Horses; D017964:Itraconazole / Q000494:pharmacology; D008825:Miconazole / Q000494:pharmacology; D010866:Natamycin / Q000494:pharmacology; D014677:Pharmaceutical Vehicles / Q000494:pharmacology
D000935:Antifungal Agents; D001548:Benzalkonium Compounds; D014677:Pharmaceutical Vehicles; D017964:Itraconazole; D008825:Miconazole; D010866:Natamycin