Ultrasound-Mediated Microbubble Delivery Of PEDF Gene Into Retina Inhibits Choroidal Neovascularization

Objectives Visual loss in age-related macular degeneration is predominantly associated with the development of CNV. Recent studies have suggested that the imbalanced expression of vessel growth stimulators and inhibitors contributes significantly to the pathogenesis of CNV. PEDF is currently believed to be the most effective factor to inhibit vessel growth. In this study, we aimed to investigate whether the ultrasound-mediated microbubble technique could enhance the transfection efficiency of PEDF plasmid, and whether CNV could be inhibited. We expect to develop a safe and effective gene delivery method for the treatment of choroidal neovascularization.Methods CNV was induced by argon laserwith a wave length of 520 nm and a spot size of 50nm at a power of 800mW for a duration of 0.05s. The lesions (8~ 10 dots) were located approximately 1 to 2 disc diameters from the optic nerve head. 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. Lesions were graded as III. Fourteen days later, fluorescein fundus angiography (FFA) was performed to confirm the development of CNV.The first part explored the difference between the ultrasound-mediated microbubble and lipofectamine. The second part explored the differences of gene injection. Gene and protein expression of PEDF in the rats'retina and choroids was detected by RT-PCR and immunofluorescence respectively. The effect of PEDF gene transfer on CNV was examined by FFA.Resluts1. 7 and 14 days later, the infection efficiency of the groups was not different, but 28 days later, the infection efficiency of the U+MB+P was higher than that of L+P With the administration of ultrasound-mediated microbubbles destruction, the CNV were inhibited effectively.2. 7, 14 and 28 d later, the infection efficiency of the groups were not different. With the administration of ultrasound-mediated microbubbles destruction, the CNV were inhibited effectively.Conclusion1. The CNV Long-Evens rat model can be made by argon laser.2. The infection efficiency of the U+MB+P was higher than that of L+P.3. The infection efficiency of the groups was not different.4. The CNV were inhibited effectively by PEDF.