Tie2-gfp Transgenic Mouse As A New Model To Study Corneal Neovascularization

Abstract

Purpose: : To describe corneal expression of Tie2 in normal and neovessel-induced cornea.

Methods: : FVB and Tie2-GFP mice were used in this study. Transgenic mice were generated in FVB background using lentivirals vectors (Tie2p/e LV) carrying the green fluorescence protein (GFP) under the control of transcription regulatory sequences of the Tie2/tek gene. Corneal neovascularization was induced by intrastromal placement of two 10.0 nylon sutures in the left eye of 4 Tie2-GFP mice. On day 8 after suture placement the mice were euthanized and eyes enucleated for corneal whole-mounts. The same procedure was performed in 4 unsutured Tie2-GFP mice and 4 FVB mice. Localization of endogenous GFP was analyzed by fluorescence deconvolution microscopy.

Results: : No fluoresecence was detected in the corneal epithelium or endothelium. In the stroma, fluorescent tubular structures projecting from the limbal arcade resembling neovessels were detected in the sutured eyes. We also detected Tie2 positive scattered cells in the corneal stroma. Interestingly, while no vessels were found, positive scattered cells were detected even in the unsutured Tie2-GFP eyes. Finally, no GFP expression was found on the FVB control corneas.

Conclusions: : Tie2 is a well-known marker for both endothelial cells and a specific subset of macrophages endowed with pro-angiogenic activity. We suggest that the Tie2-GFP mice might prove useful in studying the relationship between inflammation and neovascularization in the cornea. We expect this will enhance our understanding of the pathophysiology of this disorder.

Keywords: neovascularization • cornea: stroma and keratocytes • transgenics/knock-outs