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Ultrasonic microbubble combined with bevacizumab injection for choroidal neovascularization induced by phtocoagulation in rabbits

Objective 　To observe the therapeutic effect of ultrasonic microbubble combined with bevacizumab (Avastin) on choroidal neovascularization induced by photocoagulation in rabbits.Methods　CNV was induced by photocoagulation with argon laser in 30 rabbits (60 eyes).All of the rabbits underwent fundus fluorecein angiography (FFA) 21 days after photocoagulation; 6-8 hours later, 3 rabbits were randomly chosen to be executed to having the immunohistochemical examination.Twenty one days after photocoagulation, 27 rabbits were divided randomly into 3 groups: bevacizumb, ultrasonic microbubble + bevacizumb,and control group; each group has 9 rabbits (18 eyes).The rabbits in control group had no interference treatment; while the rats in bevacizumb and ultrasonic microbubble + bevacizumb group underwent injection with bevacizumb or ultrasonic microbubble + bevacizumb respectively.FFA was performed on all of the rabbits 7,14,and 28 days after photocoagulation to observe the inhibition of CNV; immunofluorecence and Western blot were used to detect the expression of VEGF in retina and choroid.Twentyeight days is the time point to determine the therapeutic efficacy. The expression of VEGF and the results of FFA were the sdandards of the judgement of therapeutic efficacy.Results Proliferaion of CNV to the retinal inner layer and the obvious leakage of fluoresein in the photocoagulation area indicated that the model of CNV was set up successfully. Twenty eight days after injection,obvious fluorescent leakage was found in the control group, and the average fluorescent leakage in bevacizumab group differed much from the control group（t=16.2952，Plt;0.05）; while the difference between ultrasonic microbubble + bevacizumb group and bevacizumab group was also significant (t=4.7955，Plt;0.05) . At the same time point, the expression of VEGF in bevacizumab group detected by immunofluorecent assay and Western blot differed much from the control group (t=7.0327，9.2596；Plt;0.05),and the difference of VEGF between ultrasonic microbubble + bevacizumb group and bevacizumab group was significant（t=2.9724,17.1937；Plt;0.05）. this experiment show that ultrasound combined bevacizumab intravitreal injection of the therapeutic effect of CNV superior to other groups(Plt;0.01).Conclusion Ultrasound microbubble combined with bevacizumab injection may improve the therapeutic effect on CNV by inhibiting the expression of VEGF.