Study Of The Relationship Between Cathepsin B And VEGF In Retinal Neovascularization

Objective:To establish the model of oxygen-induced mouse retinopathy, study the expression changes of Cathepsin B and VEGF in the retina of OIR model and the inhibition of Cathepsin B-RNAi-Lentivirus on retinal neovascularization and investigate the relationship between Cathepsin B and VEGF in retinal neovascularization.Methods:44 7-day-old C57BL/6J mice were randomly assigned into 4 groups: normal group,model control group, NC-GFP-Lv group and CB-RNAi-Lv group. The mice in normal group were survival in natural environment. The other three groups of 7-day-old mice were put in a sealed box of oxygen volume fraction(75 ± 2)% for 5 days and then sent back to normal environment to establish the OIR model. The mice of model control group did not have any drug intervention, while the mice of NC-GFP-Lv group and CB-RNAi-Lv group received intravitreal injection of NC-GFP-Lentivirus and Cathepsin B-RNAi-Lentivirus 1μl respectively on P13. Fluorescein angiography was used to evaluate the vascular morphology on P17. The rest mice were sacrificed and the retinas were collected. The mRNA expression levels of Cathepsin B and VEGF were performed by Real-time PCR.The protein expression levels of Cathepsin B and VEGF were detected by Western blot.Results:Under fluorescence microscope, retinal blood vessels were normal in normal group.Distroted vessels were seen in the retinas of model control group and NC-GFP-Lv group with more branches and vascular anastomosis. Vessel branches and vascular anastomosis were obviously reduced in CB-RNAi-Lv group. The mRNA and protein expression levels of Cathepsin B and VEGF of model control group were increased compared with normalgroup and the differences were statistically significant(P<0.05). The mRNA and protein expression levels of Cathepsin B and VEGF between model control group and NC-GFP-Lv group had no statistical difference(P>0.05). The mRNA and protein expression levels of Cathepsin B and VEGF of CB-RNAi-Lv group were reduced compared with NC-GFP-Lv group and the differences were statistically significant(P<0.05).Conclusion:(1) The expression levels of Cathepsin B and VEGF in retinal neovascularization of OIR model were significantly higher than normal group.(2) Cathepsin B-RNAi-lentivirus could inhibit the mRNA and protein expression levels of Cathepsin B and VEGF.(3) The expression of VEGF may be influenced by the expression of Cathepsin B.