Spontaneous corneal neovascularization in nude mice. Local imbalance between angiogenic and anti-angiogenic factors.

PURPOSE The present study considered the hypothesis that spontaneous neovascularization of the cornea of nude mice results from a local imbalance between angiogenic and anti-angiogenic factors. METHODS The presence of angiogenic and anti-angiogenic factors was revealed by exchanging orthotopic corneal allografts between nude BALB/c mice and normal (hirsute) euthymic BALB/c mice and observing the presence, intensity, and degree of corneal neovascularization before and after grafting. RESULTS Avascular corneal grafts from normal BALB/c donors resisted neovascularization after grafting to spontaneously vascularized graft beds in nude mice. In contrast, spontaneously vascularized corneal grafts from nude mice remained vascularized over 2 mo after grafting to similar nude recipients. Although corneal grafts from nude donors stimulated neovascularization in normal BALB/c recipients, most of the vessels regressed by the 6th week post transplantation. CONCLUSIONS The results confirm that there is an imbalance between angiogenic and anti-angiogenic factors in the nude mouse cornea. The cornea of the nude mouse displays more angiogenic activity and less anti-angiogenic activity than that of the normal mouse. Most angiogenic activity of the nude mouse cornea appears to reside in the epithelium.