Suppression Of Experimental Choroidal Neovascularization By Curcumin In Mice

Purpose:To investigate the effects of curcumin on the development of experimental choroidal neovascularization(CNV)with underlying cellular and molecular mechanisms.Methods:C57BL/6N mice were pretreated with intraperitoneal injections of curcumin daily for 3 days prior to laser-induced CNV,and the drug treatments were continued until the end of the study.The CNV area was analyzed by fluorescein-labeled dextran angiography of retinal pigment epithelium(RPE)-choroid flat mounts on day 7 and 14,and CNV leakage was evaluated by fluorescein angiography(FA)on day 14 after laser photocoagulation.The infiltration of F4/80 positive macrophages and GR-1 positive granulocytes were evaluated by immunohistochemistry on RPE-choroid flat mounts on day 3.Their expression in RPE-choroid complex was quantified by real-time PCR(F4/80)and Western blotting(GR-1)on day 3.RPE-choroid levels of vascular endothelial growth factor(VEGF),tumor necrosis factor(TNF)-a,monocyte chemotactic protein(MCP)-l,and intercellular adhesion molecule(ICAM)-1 were examined by ELISA on day 3.Double immunostaining of F4/80 and VEGF was performed on cryo-sections of CNV lesions on day 3.The expression of nuclear factor(NF)-?B and hypoxia-inducible factor(HIF)21a in the RPE-choroid was determined by Western blotting.Results:Curcumin-treated mice had significantly less CNV area(P<0.05)and CNV leakage(P<0.001)than vehicle-treated mice.Curcumin treatment led to significant inhibition of F4/80 positive macrophages(P<0.05)and GR-1 positive granulocytes infiltration(P,0.05).VEGF mainly expressed in F4/80 positive macrophages in laser injury sites,which was suppressed by curcumin treatment(P<0.01).Curcumin inhibited the RPE-choroid levels of TNF-a(P<0.05),MCP-1(P<0.05)and ICAM-1(P<0.05),and suppressed the activation of NF-?B in nuclear extracts(P<0.05)and the activation of HIF-1?(P<0.05).Conclusion:Curcumin treatment led to the suppression of CNV development together with inflammatory and angiogenic processes including NF-?B and HIF-1 a activation,the up-regulation of inflammatory and angiogenic cytokines,and infiltrating macrophages and granulocytes.This provides molecular and cellular evidence of the validity of curcumin supplementation as a therapeutic strategy for the suppression of age-related macular degeneration(AMD)-associated CNV.