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Avastin Inhibits the Choroidal Neovascularization in Rabbits Induced by Ultrasonic Microbubble Destruction

Author: GongZuo
Tutor: ZhouXiZuo
School: Chongqing Medical University
Course: Ophthalmology
Keywords: ultrasonic microbubble choroidal neovascularization bevacizumab VEGF
CLC: R774.1
Type: Master's thesis
Year: 2010
Downloads: 18
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Abstract

Objectives Choroidal neovascularization(CNV) has a relationship with a number of ocular fundus diseases is a common cause of blindness. The current methods of treatment are complex, expensive, less effective and stable defects. Recent studies have suggested that the imbalanced expression of vessel growth stimulators and inhibitors contributes significantly to the pathogenesis of CNV .Because of the process of CNV formation and development of vascular endothelial growth factor (VEGF) play a central role in regulating ,The role of blocking VEGF has become a hot research programs and priorities in the CNV treatment at home and abroad . Some scholars treatment of ocular neovascular disease with anti-cancer by inhibiting angiogenesis play a role in the drug–Avastin (bevacizumab) and have achieved good effect. As a new ultrasound contrast agent, ultrasound-microbubbl blasting process can effectively increase the permeability of local tissue.In this study we aim to investigate whether Avastin can inhibit the choroidal neovascularization in rabbits induced by ultrasonic microbubble.Methods CNV was induced by argon lasgon laser with a wave length of 514.5nm and a spot size of 50nm at a power of 700mW for a duration of 0.1s. The lesions (20 dots) were located approximately 2 to 3 disc diameters from the optic nerve head in rabbits. The presence of a bubble at the time of lasering was taken as an indication of the rupture of Bruch’s membrane and such injury was sufficient to induce formation of CNV.1week、2weeks、3weeks、4weeks later, fluorescein fundus angiography (FFA) and pathological examination was performed to confirm the development of CNV.After determining the model was successful, these CNV rabbits was randomly divided into three groups and were treated by infusing bevacizumab into the vitreous of rabbits;infusing Avastin and microbubbles into the vitreous of rabbits with ultrasound irradiation immediately and the CNV rabbits without any treatment served as control. Rabbits were killed and eyes were enucleated at 7, 14, and 28 days after treatment.28 days is the time point to determine efficacy.Gene and protein expression of VEGF was detected by Western blot and immunofluorescence, respectively. The effect of VEGF gene transfer on CNV was examined by fluorescein fundus angiography.Results:this experiment show that ultrasound combined Avastin intravitreal injection of the therapeutic effect of CNV superior to other groups (p< 0.05). .Resluts In the first part of this experiment show that CNV was appeared on 1 week after photocoagulation,reach peak on 3 weeks.In the first 4 weeks has stabilized.In the second part show that ultrasound combined Avastin intravitreal injection of the therapeutic effect of CNV superior to other groups(p<0.05).Conclusion1. Argon laser photocoagulation could be used to produce choroidal neovascularization experimental model in the pigment rabbits2. Avastin can effective treatment for choroidal neovascularization in rabbits3.Ultrasound-microbubble technique could increases the therapeutic effect of Avastin

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