The effect of Delta-like ligand 4 monoclonal antibody on retinal neovascularization and vascular endothelial growth factor expression / 中华实验眼科杂志

ABSTRACT

Background Studieshowed thaDelta-like ligand 4 (Dll4) participatein the deveopmenof retinal celland angiogenesis.The Dll4-Notch pathway and vasculaendothelial growth facto(VEGF) are thoughto be critical mediatorof neovascularization undehypoxiconditions.The relationship between Dll4 and VEGF inovery cleaand furtheresearch ineeded.Objective Thistudy wato observe the inhibition of Dll4 on experimental retinal neovascularization and VEGF expression.MethodThe retinal neovascularization animal model wainduced by oxygen-induced retinopathy (OIR) in 5-day-old SPF SD ratby rearing the new postnatal ratwith the motherattogethein closed box with oxygen level a(80±2) ％ till 12-day-old.The ratwere then raised in normal aifo5 days.Aftethat,2.5μl (0.5 μg) of Dll4 monoclonal antibody wainjected into the mid-vitreoucavity in the righeye(Dll4 injected group) and PBwaused in the same way in the fellow eye(PBcontrol group) in the 12-day-old rats.Retinawere isolated in the 17-day-old rats,and retinal vasculamorphology waexamined by adenosine diphosphatease (ADPase) staining of retinal flatmounts,and the endotheliocyte nuclei above the internal limiting membrane were counted in the retinal tissue-slices.Reverse transcription PC(RT-PCR) waused to detecthe mRNexpression level of Dll4,VEGF,VEGF receptor-1 (VEGFR-1),VEGFR-2 and neuropilin-1 mRNin the retinas.Statistical analysiwaperformed by the paired t-test.The care and use of the animalcomplied with the Guidance Suggestion issued by the Ministry of Science and Technology of Chinin 2006.ResultThe Dll4 mRNexpression in the retin(Dll4 mRNA/β-actin mRNA) wa0.22± 0.06 and 0.98 ± 0.13 in the Dll4 injected group and the PBcontrol group,respectively,with statistically significandifference (=21.839,P =0.000).No significandifferencewere found in the expression of the VEGF mRNA,VEGFR-1 mRNand VEGFR-2 mRNin the retinabetween the two group(t=0.463,P=0.649;=1.687,P=0.109;=-1.674,P=0.111).Compared with the PBcontrol group,the expression of neuropilin-1 mRNwasignificantly elevated in the Dll4-injected group (0.73±0.08 vs.0.64±0.07) (t=-2.677,P=0.015).ADPase staining showed thathere were much more new blood vesselin the Dll4 injected group than those of the PBcontrol group.The numbeof nuclei structurally adjacento the vitreal side of the internal limiting membrane wa(63.6± 11.6)/slide in the Dll4 injected group,which wamore than thaof the PBcontrol group a(35.1±5.2)/slide (=-7.879,P =0.000).ConclusionDll4 playan essential role in the procesof pathological angiogenesiin the retina.Dll4 ithoughto be feedback regulatoof VEGFR,which participatein the procesof restraining pathological vasculogenesis.