IN-VIVO FLUORESCENCE MICROSCOPY OF CORNEAL NEOVASCULARIZATION

Purpose: The purpose of our study was to establish an animal model to study the microcirculation in corneal neovascularization in the living animal atraumatically. Methods: Corneal neovascularization was induce d in New Zealand white rabbits by a standard micropocket assay utilizi ng pellets with 250 ng basic fibroblast growth factor. Anesthesia cons isted of intramuscular injections of ketamine and xylazine. Intravital microscopy was performed without preparation of the cornea. Rhodamine 6G was used as fluorescent dye to stain leukocytes. Fluorescein-isoth iocyanate-dextran served as plasma marker. Microcirculation analysis w as done off-line by digital video imaging with special analysis softwa re and included the following parameters: vessel diameters, blood velo city, and differentiation of leukocytes according to their interaction with endothelium into free-floating, rolling and sticking leukocytes. Results: Vessel diameters in venular trunk vessels showed diameters o f 54.0 +/- 13.3 mu m with 1.1 +/- 0.5 mm/s flow; 29.4 +/- 16.3% of all leukocytes were attached to the vascular wall. The number of sticking leukocytes was found to be 17.8 +/- 36.0 cells/mm(2) endothelial surf ace. Values are given for arteriolar trunk and branch as well as venul ar branch vessels. Conclusions: This method for in vivo microscopic ob servation and quantification of the vasculature of the ocular surface seems to be suitable for evaluation of microhemodynamic and leukocyte measurements in mature neovascular vessels. It allows atraumatic exper iments without corneal preparation procedures which disturb the microc irculation. The results concerning microhemodynamics and adherence of leukocytes are in a range comparable to other microcirculation studies . This new model could provide insight into the pathophysiology of mic rocirculatory disorders of the anterior eye segment, e.g. during angio genesis.