Abstract
Purpose: :
To evaluate the angiostatic effect of topically administered ascorbic acid, both non pH–neutralized and pH–neutralized, on silver nitrate–induced corneal neovascularization in the rat.
Methods: :
Corneal neovascularization was induced secondary to inflammation incited by silver nitrate cautery in the rat eye. Seventy–two Long Evans rats were divided into eight groups. The animals were treated in accordance with the ARVO guidelines on the care and use of animals in research. After corneal cauterization, the eyes received one drop twice per day of either pH–neutralized ascorbic acid (100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 500 µg/ml or 250 µg/ml); 100 mg/ml of non pH–neutralized ascorbic acid; or normal saline. The study lasted seven days. The percent area of corneal neovascularization was determined with digital image analysis.
Results: :
Topically applied pH–neutralized ascorbic acid in concentrations of 100 mg/ml (p<0.01), 50 mg/ml (p<0.01), 10 mg/ml (p<0.01), 5 mg/ml (p<0.01), 1 mg/ml (p<0.01) and 500 µg/ml (p<0.05) appears to inhibit corneal neovascularization in the rat model. The concentration of 250 µg/ml did not significantly inhibit angiogenesis compared with the control group (p>0.05). Non pH–neutralized ascorbic acid (100 mg/ml) also significantly inhibited corneal angiogenesis (p<0.01).
Conclusions: :
Topical treatment with both pH–neutralized and non pH–neutralized ascorbic acid inhibited angiogenesis in an experimentally induced inflammatory corneal neovascularization in the rat eye.
Keywords: drug toxicity/drug effects