Characterization and quantification of copper sulfate-induced vascularization of the rabbit cornea

A model of angiogenesis in the rabbit cornea, with reproducible onset and duration of responses, was developed by using CuSO4 as the angiogenic stimulus. The vascularization of the cornea was quantified by means of an image analyzer. In addition, the effects of antiinflammatory compounds, dexamethasone and flurbiprofen, on the angiogenic response to CuSO4 were examined. Elvax pellets containing 10-75 micrograms of CuSO4 implanted in the corneal stroma dose-dependently induced neovascularization, which persisted for more than 64 days at the highest dose. Manual measurements of blood vessel lengths and image analysis measurements of blood vessel areas were comparable during the growth phase of vascularization, but only the image analysis measurements detected a subsequent regression phase. Therefore, the length method of measurement is only useful during the growth phase, whereas the image analysis method is useful during both the growth and regression phases of vascularization. Dexamethasone (50 micrograms, applied topically, three times a day) and flurbiprofen (100 micrograms, applied topically, three times a day) suppressed the inflammation produced by corneal implants containing 75 micrograms CuSO4. However, each drug only inhibited vascular growth by 50% during the 14 days of treatment. Although CuSO4 is not an endogenous angiogenic factor, the model presented in this report may be useful in quantitative evaluation of anti-angiogenic agents.