Experimental Study On Effect Of Corneal Neovascu Larization Treated With N～G-Nitro-L-Arginine Methyl Ester (L-NAME) After Alkali Burn

Objective To investigate the expression of inducible nitric oxide synthase(iNOS) in cornea after alkaline bum; to observe the effect of topically applied N~G-Nitro-L-Arginine Methyl Ester(L-NAME) on corneal neovascularization (CNV) in rats.Methods Corneal neovascularization model was established by putting the filter paper with the size of 3mm in diameter were immerse in lmol·L~-1 NaOH solution on the rat cornea for 90 seconds. Fifty Sprague-Dawley rats were randomly divided into 3 study groups (A B C groups), a control group and a normal one. The L-NAME drops with different concentrations were applied topically to rat corneas four times daily for four weeks on each group: 3g·L~-1 in group A, 10g·L~-1 in group B, 30g·L~-1 in group C, carrier solution in group D(control) and 30mg/L in group E(normal). Slit-lamp biomicroscopy and photography, immunohistochemical staining were done; the area of CNV were calculated and the everage optic density of immunohistochemical staining of iNOS were measured on 8hours,l,4,7,14,28days by imaging analysis system. Meanwhile, the toxicity effects of topically applied L-NAME were tested.Results The expression of iNOS mainly located into the inflammatory cells in corneal stroma layer and endothelial cells of neovascularization. The difference in the expression of iNOS and the area of neovascularization between group B C and group A D were statistically significant (P<0.05). All rats with repeatedly and topically applied L-NAME were well tolerated.Conclusion Topical application of L-NAME are effective in the inhibition of corneal neovascularization induced by alkaline burn; The levels of iNOS were markly related to inflammatory corneal neovascularization; In addition, it is a safe way to apply L-NAME topically without the obvious side effects occurring.