Abstract
Abstract: :
Purpose: Spontaneous chronic corneal epithelial defects (SCCEDs) in dogs and humans are characterized by persistence of an epithelial defect with non–adherent epithelium surrounding the denuded stroma. Samples obtained from canine patients demonstrate sheets of poorly adherent epithelial cells, absence of basement membrane components, and the presence of a stromal superficial hyalinized acellular zone. Matrix metalloproteinases (MMPs) remodel the extracellular matrix and are reported to be altered during normal wound healing and in various pathological processes, including recurrent erosions in humans. Here we report MMP activity to be modulated during normal wound healing in dogs and in canine patients with SCCEDs. Methods: Right eyes of 8 normal dogs underwent mechanical epithelial debridement. 24 (n=4) or 48 hours (n=4) post–wounding the dogs were euthanized and corneas collected. Superficial keratectomies were performed on canine SCCED patients for therapeutic reasons, and samples were collected for analysis. Samples were homogenized and supernatants were collected. Zymography was performed as previously described. Results: 24 and 48 hour wounded corneas showed significant up–regulation of MMP–9 (p value =.004 and p value =.042, respectively). There was no significant difference in values for MMP–2 in wounded corneas versus controls. For SCCED samples, however, there was a significant increase in MMP–2 (p= 0.011) compared to normal eyes. Conclusions: Wounded corneas show significant increase in MMP–9 during corneal epithelial wound healing and SCCED samples showed an increase in MMP–2. These findings are in accord with published results obtained from human clinical corneal epithelial specimens from patients with recurrent epithelial erosions.
Keywords: wound healing • cornea: clinical science • cornea: epithelium