Abstract
Purpose: :
The purpose of this study was to investigate the effect of carboxymethyl chitosan (CMC) on dog dry eye model induced by topical application of a benzalkonium chloride (BAC).
Methods: :
Fifteen healthy adult male Beagle dogs were used and dry eye model was induced by instilling 0.4% BAC eye drops four times daily for 4 weeks. Sterile distilled water (control group), artificial tears, and 0.5% CMC eye drops were applied from 14 days to 4 weeks after 0.4% BAC eye drops application. Schirmer tear test (STT), fluorescein, and rose bengal staining were performed before and after BAC treatment. Hematoxylin-eosin, periodic acid Schiff (PAS), and immunohistochemical stainings were performed to evaluate general histopathology, goblet cells, and the patterns of TNF-α, poly (ADP-ribose) polymerase (PARP), and caspase-3 expressions.
Results: :
Schirmer scores of CMC treated eyes were significantly higher than control group on days 7, 10, and 14 (p<0.05). Fluorescein and rose beengal scores were significantly decreased in CMC treated group compared with control group (p<0.05). Cornea and conjunctiva epithelial thicknesses significantly increased in group 2 and group 3 (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 increased in CMC treated eyes. In addition, the numbers of inflammatory cells, TNF-α, caspase-3, and PARP positive cells significantly reduced in CMC treated ocular surface tissues (p<0.05).
Conclusions: :
The results of this study suggest that topical application of 0.5% CMC eye drops may have a beneficial effect on dog dry eye induced by 0.4% BAC topical application by regeneration of damaged ocular surface and alleviation of its inflammatory and apoptotic processes.
Keywords: cornea: tears/tear film/dry eye