Purchase this article with an account.
G. M. Gordon, J. S. Austin, A. J. LaGier, M. E. Fini; Global MMP Profile in the Resurfacing Corneal Epithelium: Identifying the Players. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3494.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Matrix Metalloproteinases (MMPs) have been shown to play an important role in corneal wound healing. For example, abrasion wounds in MMP-9 knockout mice resurface faster than in wild type controls though broad spectrum MMP inhibitors impair resurfacing suggesting other MMPs are playing critical roles in the wound healing process. This study looks at the up and down-regulation of the entire MMP family during corneal re-epithelialization.
A 1mm trephine was used to demarcate the wound area in FVB mice ages 6-8 weeks. An Algerbrush II® (The Alger Company, Inc) was used to debride the corneal epithelium down to the basement membrane from the right eye of each mouse. The left eye was left unwounded as a contralateral control. Corneal epithelial cells migrating to cover the wound area were scraped at 18 (still resurfacing) and 24 hours (fully resurfaced) post wounding into TRIzol where the RNA was subsequently purified. Two step semi-quantitative RT-PCR was performed on RNA. PCR products were confirmed by melt curves or running on 2% agarose gels. Statistical significance was determined by the paired Wilcoxen test.
While a few studies have identified the expression of one or two MMPs in corneal wound healing models, a global MMP signature would help define all MMPs playing key roles in corneal wound healing. We analyzed the in vivo temporal expression patterns of all 23 known mammalian MMPs in migrating epithelial cells of 10 mice by RT-PCR. We then used antibodies to define the spatial-temporal localization of all MMPs that underwent a significant change in expression. We found that MMPs 1a, 1b, 9, 10, and 13 were significantly up-regulated at 18 hours post-wounding. Following complete resurfacing, all of these MMPs were downregulated though MMPs 1a, 1b and 13 were still significantly up-regulated compared to the unwounded controls perhaps indicating further roles in the wound healing process. MMP-9 and MMP-10 showed very specific immunolocalization patterns; MMP-9 was immunolocalized to the leading edge of the migrating front while MMP-10 was localized behind the leading edge. MMP-13 was immunolocalized to the entire wound area.
This is the first global signature for MMP expression in a wound healing model. Preliminary findings have identified several MMPs which may play significant roles during corneal resurfacing. Completion of this study will also include the expression patterns of MMP regulators such as TIMPs and ADAMs. Future experiments using knockout mice are in progress to fully understand the functions of these individual MMPs during re-epithelialization.
This PDF is available to Subscribers Only