Ketorolac inhibits choroidal neovascularization by suppression of retinal VEGF

Abstract

We assessed the effect of topical ketorolac on laser-induced choroidal neovascularization (CNV), measured retinal PGE(2) and VEGF levels after laser treatment, and determined the effect of ketorolac on PGE(2) and VEGF production. Six laser burns were placed in eyes of rats which then received topical ketorolac 0.4% or artificial tears four times daily until sacrifice. Fluorescein angiography (FA) was performed at 2 and 3 weeks and retinal pigment epithelium-choroid-sclera flat mounts were prepared. The retina and vitreous were isolated at 1, 3, 5, 7, and 14 days after laser treatment and tested for VEGF and PGE(2). Additional animals were lasered and treated with topical ketorolac or artificial tears and tested at 3 and 7 days for retinal and vitreous VEGF and PGE(2.) Ketorolac reduced CNV on FA by 27% at 2 weeks (P<0.001) and 25% at 3 weeks (P<0.001). Baseline retina and vitreous PGE(2) levels were 29.4 μg/g and 16.5 μg/g respectively, and reached 51.2 μg/g and 26.9 μg/g respectively, 24h after laser treatment (P<0.05). Retinal VEGF level was 781pg/g 24h after laser treatment and reached 931pg/g by 7 days (P<0.01). Ketorolac reduced retinal PGE(2) by 35% at 3 days (P<0.05) and 29% at 7 days (P<0.001) and retinal VEGF by 31% at 3 days (P=0.10) and 19% at 7 days (P<0.001). Topical ketorolac inhibited CNV and suppressed retinal PGE(2) and VEGF production.

Fig. 1

Representative fluorescein angiogram images of laser-induced choroidal neovascularization (CNV) at 2 and 3 weeks.

Fig. 2

Mean pixel area of CNV lesions measured on fluorescein angiogram at 2 and 3 weeks after treatment with ketorolac or artificial tears. Error bars represent 95% confidence intervals (CI). *P < 0.00001. **P < 0.0001.

Fig. 3

Representative choroidal flat mounts demonstrating laser-induced CNV and degree of vascular budding in eyes treated with ketorolac or artificial tears at 3 weeks.

Fig. 4

Mean pixel area of CNV lesions measured on choroidal flat mounts at 3 weeks after treatment with ketorolac or artificial tears. Error bars represent 95% CI. *P < 0.00001.

Fig. 5

Mean PGE₂ concentration in the retina and vitreous before and after laser-induced choroidal neovascularization (LCNV). PGE₂ concentration at 1 day after LCNV was significantly greater than baseline in both the retina and vitreous. *P < 0.05.

Fig. 6

Mean VEGF concentration in the retina and vitreous before and after LCNV. Compared to day 1 after LCNV, retinal and vitreal VEGF concentrations reached their highest level at 7 days (P < 0.01) and 5 days (P < 0.001) respectively.

Fig. 7

Retina and vitreous PGE₂ concentration at 3 and 7 days after LCNV. Three days after laser treatment, ketorolac significantly reduced retinal PGE₂ by 35% (P < 0.05) compared to eyes treated with artificial tears. At 7 days, ketorolac significantly reduced retinal PGE₂ by 29% (P < 0.001) and vitreous PGE₂ by 11% (P < 0.05).

Fig. 8

Retina and vitreous VEGF concentration at 3 and 7 days after LCNV. At 3 days, ketorolac reduced retinal VEGF by 31% compared to eyes treated with artificial tears (P = 0.10). At 7 days, ketorolac significantly reduced retinal VEGF by 19% (P < 0.001). At both 3 and 7 days vitreous VEGF concentrations were not significantly different between ketorolac and artificial tear-treated groups.