Abstract
Purpose: :
To establish a dog dry eye model induced by topical application of benzalkonium chloride (BAC).
Methods: :
Twenty healthy adult male Beagle dogs were used. A sterile distilled water (control group), 0.1% BAC, 0.2% BAC and 0.4% BAC eye drops were applied four times daily for 2 weeks. Schirmer tear test, fluorescein and rose bengal staining were performed on days 0, 3, 7, 10 and 14. The dogs were euthanized on day 14. Hematoxylin-eosin, periodic acid Schiff (PAS), and immunohistochemical stainings were performed to evaluate general histopathology, number of goblet cells and the patterns of TNF-α, poly (ADP-ribose) polymerase (PARP) and caspase-3 expressions.
Results: :
Schirmer scores of 0.4% BAC treared eye were significantly lower than control group on days 3, 7, 10, 14 (p<0.05). Fluorescein and rose bengal staining scores were significantly increased in 0.4% BAC treated group compared with control group on days 3, 7, 10, and 14 (p<0.05). In the histological examination, the thickness of damaged corneal and conjuctival epithelial layers and the number of goblet cells of conjunctiva were markedly decreased in 0.4% BAC treated eyes. In addition, the numbers of inflammatory cells, TNF-α, caspase-3, and PARP positive cells were significantly increased in 0.4% BAC treated ocular surface tissues (p<0.05).
Conclusions: :
The results of this study suggest that topical application of 0.4% BAC eye drops induced a dry eye in dogs with decreased tear secretion, damage of ocular surface and promotion of its inflammatory and apoptotic processes.
Keywords: cornea: tears/tear film/dry eye • cornea: basic science • cornea: epithelium