RESUMO
Objective To observe the expression ofRapl,guanosine triphosphate-Rapl (GTP-Rapl),vascular endothelial growth factor (VEGF) and β-catenin in experimental choroidal neovascularization (CNV).Methods Forty-two brown Norwegian rats were randomly divided into a blank control group (7 rats) and a model group (35 rats).Both eyes were enrolled.The CNV model was established by holmium ion laser photocoagulation in the model group.At 3,7,14,21,and 28 days after photocoagulation,fluorescein fundus angiography (FFA) and choroidal vascular smear were performed to observe the degree of fluorescein leakage and CNV area in rats;Western blot and real-time quantitative polymerase chain reaction (RT-PCR) were used to detect the expression ofRap1,GTP-Rap1,VEGF,β-catenin and mRNA in CNV.Results The results of FFA examination showed that a large disc-shaped fluorescein leaked in the photo-condensation spot 14 days after photocoagulation.Laser confocal microscopy showed that compared with 7 days after photocoagulation,CNV area increased at 14,21,28 days after photocoagulation,and the difference were statistically significant (t=3.725,5.532,3.605;P＜0.05).Western blot showed that there was no significant difference in the relative expression of Rap1 protein in CNV at different time points after photocoagulation between the two groups (P=0.156).Compared with the blank control group,the relative expression of GTP-Rap1 protein was significantlydecreased,the relative expression of VEGF and β-catenin protein were significantly increased in the model group (P=0.000).The results of RT-PCR showed that there was no significant difference in the relative expression of Rap 1 mRNA at different time points after photocoagulation between the two groups (P=0.645),but there were significant difference in the relative expression of β-catenin mRNA (P=0.000).At 7,14,21 and 28 days after photocoagulation,there were significant difference in the relative expression of GTP-Rap 1 and VEGF mRNA between the two groups (P=0.000).Conclusions The expression of GTP-Rap1 in experimental CNV is significantly lower than that in normal rats.
RESUMO
Retinal neovascularization,a common pathological process of a variety of eye diseases,is a major cause of blindness.Vascular endothelial growth factor (VEGF) has been believed to be the most important therapeutic target of neovascular eye diseases.In the era of anti-VEGF for retinal diseases,several drugs aiming at the single molecular target VEGF-A have achieved considerable success in decreasing neovascularization and relieving the symptoms.In the past two years,novel anti-VEGF drugs aiming at multiple molecular targets including VEGF-A,VEGF-B and PlGF have surged into clinic service.Represented by aflibercept (VEGF Trap-Eye,Eylea) and conbercept (KH902),multiple targets anti-VEGF drugs relieve the clinical symptoms in patients resistant to single target anti-VEGF drugs.In addition,because similar curative effects are achieved with longer injection interval,risk of complications related to the intraocular injection procedure is reduced.However,it is reported that the additional inhibited targets are associated with maintaining the normal functions of blood vessels and neurons.Therefore,although there are still no severe adverse effects for these new developed drugs,further long-term observation is mandatory to evaluate their safety.In this review,we summarized the characteristics of aflibercept and conbercept,a new generation of anti-VEGF drugs,from the aspects of basic research,pharmacokinetics,efficacy,safety and the existing problems.