Phosphorothioate oligonucleotides induction into experimental choroidal neovascularization by HVJ-liposome system

Purpose. The purpose of this study was to determine whether the inactivated hemagglutinating virus of Japan (HVJ)liposome method can induce phosphorot hioate oligonucleotides effectively into an experimentally-induced choroida l neovascularization of rats. We also examined whether antisense phosphorot hioate oligonucleotides against VEGF could be induced into choroidal neovas cularization as a therapeutic agent by the HVJ-liposome method. Methods. The experiments were conducted on a rat model of choroidal neovasc ularization. FITC-labeled phosphorothioate oligonucleotides were coencapsul ated in liposomes. The liposomes were coated with the envelope of inactivat ed HVJ and injected into the vitreous cavity following photocoagulation of- pigmented rat eyes. The eyes were removed following injection, fixed, froze n and cut into thin sections. Induction of oligonucleotides was observed un der a laser confocal scanning microscope for fluorescence and the developme nt of choroidal neovascularization was evaluated histopathologically. Results. Phosphorothioate oligonucleotides were effectively induced into ga nglion cells and into the cells of the choroidal neovascularization induced by laser photocoagulation. Highly effective induction of oligos was observ ed 3 to 14 days after intravitreal injection of HVJ-liposomes after which t he level decreased. Antisense oligonucleotides against VEGF were induced sp ecifically into cells in the choroidal neovascularization, however neovascu larization was still observed. Conclusions. Phosphorothioate oligonucleotides can be effectively induced i nto ganglion cells, and specifically into cells in choroidal neovasculariza tion. Although antisense oligonucleotides against VEGF failed to prevent ch oroidal neovascularization, the HVJ-liposome method provided a highly effec tive means of inducing antisense oligos for in vivo antisense therapy.