Study On The Role Of Notch1 And Dll4 In Neovascularization Of Diabetic Retinopathy

Objective: To study the effect of Notch1 and Dll4 in the proess of neovascularization of proliferative diabetic retinopathy(PDR) and its relationship with vascular endothelial growth factor receptor2(VEGFR2) by detecting the expressions of the Notch1、Dll4 and VEGFR2 in the preretinal fibrovascular membranes from PDR patients and epiretinal membranes from non-diabetic patients.Methods: Sisty preretinal fibrovascular membranes obtained from the patients with PDR during vitrectomy were viewed as PDR group,28 of them received Lucentis intravitreally before surgery and the other 32 did not.Eighteen epiretinal membranes obtaining from the non-diabetic patients served as controls.The quantitative real-time polymerase chain reaction and immunohistochemical methods were used to detecting the expressions of Notch1、Dll4 and VEGFR2.In the meantime,the numbles of the nucleus of vascular endothelial cells in the membranes stained with hematoxylin were counted.Results:1.The real-time polymerase chain reaction(RT-PCR) show that the difference of the m RNA expressions of Notch1、Dll4 and VEGFR2 were statistically significant among the PDR group and control group(HNotch1 m RNA =12.500,PNotch1 m RNA =0.002<0.05;HDll4 m RNA =12.500, PDll4 m RNA =0.002<0.05; HVEGF R2 m RNA=12.020, PVEGFR2 m RNA=0.002<0.05).The expressions of Notch1、Dll4 and VEGFR2 in the PDR membranes were higher than those of epiretinal membranes from non-diabetic patients;In the PDR group,the expressions of Notch1、Dll4 and VEGFR2 of the PDR group without Lucentis were higher than those of the Lucentis group.The spearman correlation analysis showed that the expression of m RN A between VEGFR2 and Notch1、VEGFR2 and Dll4、Notch1 and Dll4 were significantly correlated(P<0.05),the correlation coefficient was 0.83、0.81、0.87 respectively. 2.The immunohistochemical staining revealed that there were positive expressions of Notch1、Dll4 and VEGFR2 in all 57 PDR membranes,regardless of the injection of the Lucentis.The levels of Notch1、Dll4 and VEGFR2 protein in the group without Lucentis were higher than that of the Lucentis group(PNotch1=0.030、PDll4=0.008、PVEGFR2=0.023).In the group with Lucentis,the number of endothelial cells in the membranes did reduce(17.17±2.48,n=10),compared with that of the group without Lucentis(41.50±5.57,n=12).There was stastically significance aboat the difference in the numble of endothelial cells in the membranes between the two groups(t=9.58,P<0.05).Conclusions:The Dll4/Notch1 pathway may regulate and control the neovascularization by affecting the proliferation of the endothelial cells of the new vessels;The expression of Notch1、Dll4 may play a regulatory rule in the neovascularization in the proliferative diabetic retinopathy,the acting way may be correlated with VEGFR2.