The effect of Notch1 and Delta-like ligand 4 in the neovascularization of the proliferative diabetic retinopathy / 中华眼底病杂志

ABSTRACT

Objective o observe the expression of Notch1 and Delta-like ligand 4 (Dll4) on the fibrovascular membranes in proliferative diabetic retinopathy (PDR),and investigate its relationship with vascular endothelial growth factor receptor 2 (VEGFR2).Methods Fifty-seven PDR patients (60 eyes) who underwent vitrectomy were enrolled in this study.The PDR patients were divided into non-injection group (30 patients,32 eyes) and injection group (27 patients,28 eyes).The eyes in injection group received intravitreal injection with ranibizumab at 2 to 7 days before surgery.The preretinal fibrovascular membranes were obtained from the PDR patients during vitrectomy.Eighteen epiretinal membranes were obtained from the non-diabetic patients was served as controls.The real-time polymerase chain reaction (RT-PCR) and immunohistochemical methods were used to detecting the expression ofNotch1,Dll4 and VEGFR2.In the meantime,the numbers of the nucleus of vascular endothelial cells in the membranes stained with hematoxylin were counted.Results The immunohistochemical staining revealed that there were positive expression ofNotch1,Dll4 and VEGFR2 in all PDR membranes,regardless of the injection of the ranibizumab.The levels ofNotch1,Dll4 and VEGFR2 protein in non-injection group were higher than those of injection group (t=3.45,6.01,4.08;P=0.030,0.008,0.023).In injection group,the number of endothelial cells in the membranes reduced (17.17 ± 2.48) compared with that of the non-injection group (41.50± 5.57).There was significant difference in the number of endothelial cells in the membranes between the two groups (t=9.58,P＜0.05).RT-PCR showed that the differences of the mRNA expression ofNotch1,Dll4 and VEGFR2 were all statistically significant among the PDR group and control group (H=12.50,12.50,12.02;P＜0.05).The expression ofNotch1,Dll4 and VEGFR2 in the PDR membranes was higher than that of epiretinal membranes from non-diabetic patients.In the PDR group,the expression of Notch1,Dll4 and VEGFR2 of non-injection group was higher than that of injection group.Spearman correlation analysis showed that the expression of mRNA between VEGFR2 and Dll4 (r=0.83),VEGFR2 and Notch1 (r=0.81),Notch1 and Dll4 (r=0.87) were all significantly correlated (P＜0.05).Conclusions The expression of Notch1 and Dll4 in the PDR membranes are higher than that of the control group,and it is positively correlated with the expression of the VEGFR2.Notchl and Dll4 play a regulatory rule in the neovascularization in PDR,the acting way may be correlated with VEGFR2.