Purpose
To confirm the role of epithelium-derived connective tissue growth factor in corneal scarring, a congenital tissue-specific knockout strategy was employed.
Methods
Mice homozygous for floxed CTGF alleles were bred with mice containing a Cre-recombinase transgene under control of a PAX6 promoter. In the past, this promoter has led to expression specifically in the cornea and lens epithelia. We then planned to observe how the corneas responded to an excimer laser phototherapeutic keratecomy wound model.
Results
The mice were born and remained viable, however; their corneas, irises, and lenses were grossly malformed. Corneas presented with a mixed phenotype where some corneas appeared fine, while others had inconsistent patterns of opacities with variable opacity. The irises were either not present, or severely malformed, including frequently they appeared swollen and smooth with a very rounded, doughnut-like edge at the pupil. Occasionally, pieces of the iris were found adhered to the lens and separated from the rest of the iris.
Conclusions
Corneas without CTGF in their epithelium can still form corneal opacities. While unexpected, these results have some characteristics which are similar to those who suffer from aniridia, in particular, the spontaneous formation of corneal opacities. While some characteristics of aniridia would not be therapeutically addressable, this mouse model may be a good research model for studying the spontaneous opacification of the cornea which does occur in patients with aniridia and may therefor aid in remedying this blinding component of this disorder.
Keywords: 543 growth factors/growth factor receptors •
571 iris •
480 cornea: basic science