Ultrasound–Mediated Gene Transfer Into Rat Retina Using Micro–Bubbles

Abstract

Abstract: : Purpose: It is known that ultrasound (US) can enhance the gene transfer to mammalian cells without apparent damage. Moreover, the simultaneous use of micro–bubbles significantly increases the efficiency of US–mediated gene transfer. We have previously demonstrated the ability of US–mediated gene transfer into rabbit cornea. In this study, we show the gene transfer to retina in vivo medicated by US and micro–bubbles focusing of its efficacy and safety. Methods: Plasmid expressing luciferase DNA was inoculated into vitreous cavity of 10 W–old Wister rat (5mg/10ml) through 33G needle with or without micro–bubbles (3.3mg/10ml , Optison ^TM). Then, the eyes were exposed to US (Sonitron2000^TM) through cornea under different intensities (1 mHz, power; 0.5∼2 W, duration; 60 or 120 seconds, duty ratio; 10 to 100 %). 48hours later, the retinas were separated from the enucleated eyes, homogenized and measured the luciferase intensity. Histopathological examination was also performed to evaluate the damage of retina. Results:Compare to non–US group, US increased the efficacy of gene transfer into rat retina. (Optimal US condition: 2W/cm², 1 mHz, duty ratio 50% and 480 second exposure). In contrast to in vitro data, we found co–exposure with micro–bubbles did not increase the gene transfer in vivo. There were no apparent damaged area in the HE–stained sections of retina. Conclusions: We confirm the utility of US–mediated gene transfer into retina in vivo without serious side effects. Proprietory interest: None

Keywords: gene transfer/gene therapy • retinal pigment epithelium