Oral and ocular administration of crocetin prevents retinal edema in a murine retinal vein occlusion model

PURPOSE: We investigated the effects of oral and ocular administration of crocetin in a murine retinal vein occlusion (RVO) model. Crocetin is a type of carotenoid contained in the fruit of gardenia (Gardenia jasminoides Ellis) and the stigma of saffron (Crocus staruts L). METHODS: This study was performed on a murine RVO model, which was created by laser irradiation of retinal veins. We evaluated the retinal thickness after the oral administration of crocetin (100 mg/kg) 1 and 6 h before laser irradiation, and immediately, 6 h, 12 h, and 18 h after laser irradiation in the murine RVO model. In addition, we measured the retinal layer thickness after administration of crocetin eye drops (0.03% or 0.10%) immediately, 6 h, and 12 h after laser irradiation. Western blotting of retinal tissue was used to determine the expression levels of matrix metalloproteinase (MMP-9), tumor nuclear factor (TNF-α), and occludin after oral administration of crocetin. RESULTS: Oral and ocular administration of crocetin improved retinal edema in the murine RVO model. Crocetin administration statistically significantly suppressed overexpression of MMP-9 and TNF-α, and reversed the reduction of occludin. CONCLUSIONS: These findings indicate that crocetin can protect retinal tight junctions by suppressing retinal edema through an anti-inflammatory effect, which suggests that crocetin may be useful for RVO disease.