Abstract
Purpose:
Delayed healing of the corneal epithelial defect may be associated with sight-threatening complications. To understand the mechanisms underlying delayed epithelial wound healing in diabetic corneas, we investigated Wnt signaling pathway and its function in healing CECs of normal and type I diabetes mellitus (DM) rat corneas.
Methods:
To create an epithelial wound, corneal epithelial cells marked by 5 mm trephine were removed and collected from streptozotocin (STZ) and age-matched Sprague-Dawley rats. Wound healing was monitored by fluorescein staining. At 40 hours post wounding, Wnt2 expression was determined by RT-PCR, Western blot analysis. The distribution of Wnt2 and beta-catenin in rat corneas was examined by Immunofluorescence staining.
Results:
Our genome-wide cDNA array results showed that the expressions of multiple Wnts were altered in response to wounding. Among these Wnts, Wnt2 expression was further downregulated in diabetic corneal epithelium. RT- and realtime PCR confirmed the differential expression pattern of Wnt2. Both Western blotting and immunohistochemistry revealed that Wnt2 expression was down-regulated in migrating epithelial sheet of normal cornea and almost undetectable in DM cornea. Moreover, beta-catenin, a Wnt2 downstream signaling protein, was also shown an altered distribution in healing corneas.
Conclusions:
Our results suggest Wnt signaling is important for corneal epithelial wound healing and that downregulation of Wnt2 may be responsible, in part, for the delayed epithelial wound closure in diabetic rat corneas.
Keywords: 482 cornea: epithelium •
498 diabetes