Inhibitory effect of radixin shRNA on retinal neovascularization induced by hyperoxia in mice / 中华实验眼科杂志

ABSTRACT

Background Retinal neovascularization is pathological basis of a variety of fundus diseases,but its pathogenesis is unclear.Studies showed that the expression level of radixin in retina is remarkably increased in retinal neovascularization-related diseases.It is presumed that silencing or down-regulating the abnormal expression of radixin is helpful for curing retinal neovascularization-related diseases.Objective This study was to investigate the inhibitory effect of radixin short hairpin RNA (shRNA) plasmid on expression of radixin gene in retina of oxygen-induced retinopathy (OIR) mice.Methods Sixty-four 7-day-old C57BL/6J mice were randomly divided into normal control group, model control group, radixin shRNA plasmid group and shRNA plasmid group by random number table.There were 16 mice in every group.OIR models were established by exposing the mice in an environment of (75±2) ％ oxygen for 5 days and then returned to the normal air in the model control group,radixin shRNA plasmid group and shRNA plasmid group,while the mice of the normal control group were fed in the normal air environment.Radixin shRNA plasmid or control shRNA plasmid at the dose of 1 μg was intravitreally injected in 12-day-old mice of the radixin shRNA plasmid group or shRNA plasmid group, respectively.Five days later, FD-2000S angiography was performed on the mice of each group and then retinal flatmounts were prepared for the observation of retinal vessels.The mice from various groups were sacrificed and retinal sections were prepared.The vascular endothelial nucleus and new blood vessels extending inner limiting membrane (ILM) were examined by hematoxylin and eosin staining;the expression of radixin in the retinas was detected using immunochemistry;the relative expression levels of radixin mRNA and protein were quantitative assayed by real-time quantitative RCR and Western blot, respectively.The use and care of the animals adhered to the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research.Results The distribution of retinal vessels was normal in the normal control group.Non-perfusion zone at the posterior pole of retina, circuity of blood vessels,leakage of vessel wall and new blood vessels were found in the mice of the model control group.Non-perfusion zone and microaneurysms were also exhibited in the shRNA plasmid group.However,these findings were slight in the radixin shRNA plasmid group.The surface of ILM was in discontinuity in the model mice and shRNA-injected mice with more vascular endothelial cell nucleus and more tubes extending ILM than that in the radixin shRNA plasmid group.The immunochemistry results showed that the expressions of radixin in the normal control group and radixin shRNA plasmid group were weaker than those in the model control group and control shRNA plasmid group.The relative expression levels of radixin mRNA were 1.002±0.043,2.236-±0.093,0.556±0.015 and 2.272±0.096 in the normal control group, model control group,radixin shRNA plasmid group and control shRNA plasmid group,and those in the radixin shRNA plasmid group were significantly reduced in comparison with the normal control group, model control group and the shRNA plasmid group (all at P＜0.01).The relative expression levels were 1.000±0.082,1.193±0.021,0.263± 0.016 and 1.235±0.005 in the normal control group,model control group,radixin shRNA plasmid group and shRNA plasmid,with the lowest expression level in the radixin shRNA plasmid group (all at P＜0.01).Conclusions Radixin shRNA can downregulate the expression of radixin gene in the retinas of OIR mice and further inhibit pathological retinal neovascularization.