A siRNA targeting vascular endothelial growth factor-A inhibiting experimental corneal neovascularization.

PURPOSE: This study was designed to investigate whether synthetic small interference RNA (siRNA) targeting VEGF-A could inhibit mouse corneal neovascularization or not.

METHODS: First, the effect of synthetic siRNA targeting VEGF-A on the expression of VEGF in human retinal pigment epithelial line ARPE-19 cells was examined. Corneal neovascularization was induced on the right cornea of C57BL/6 mice by alkali burn. Mice were randomly divided into 4 groups (21 animals in each group): VEGF-A siRNA group, stable negative siRNA group, saline control group, and blank control group. After alkali burn, except for the blank control group, the other 3 groups were subconjunctivally injected with VEGF-A siRNA, stable negative siRNA, and normal saline, respectively. On days 3 and 7 after alkali burn, the concentration of VEGF in the cornea was determined by ELISA kit. On day 10, the neovascularized corneal area was mensurated, the amount of corneal new vessels was quantified by CD31 immunohistochemical assay of corneal sections, and permeability of new vessels was shown by fluorescence angiography.

RESULTS: After comparing the histological appearance of the cornea between the VGF-A siRNA group and the 3 control groups on days 10 and 30, it was found that in the VEGF-A siRNA group, not only was VEGF expression in the cornea induced by alkali burn but also neovascularized corneal area and amount of new vessels were reduced, followed by the permeability of new vessels, and corneal histological structure were improved. It was also found that the exposure to VEGF-A siRNA significantly reduced the VEGF-A mRNA expression in AREP-19 cells. These findings suggested synthetic siRNA targeting VEGF-A delivered by subconjunctival injection could inhibit corneal angiogenesis induced by alkali burn.

CONCLUSION: VEGF-A siRNA could potentially serve as an important therapeutic alternative in the management against unwanted angiogenesis including corneal neovascularization.