Subconjunctival Injection of Recombinant Adenovirus-Vasostatin Attenuates the Development of Choroidal Neovascularization in Rats Model

Abstract

Purpose: : Vasostatin, the N-terminal domain of calreticulin, is a potent angiogenesis inhibitor. This study was designed to investigate the effects of subconjunctival injection of recombinant adenovirus-vasostatin on experimental choroidal neovascularization (CNV) in rats.

Methods: : Recombinant adenovirus-vasostatin, adenovirus, and adenovirus-luciferase were constructed. CNV was induced in Brown Norway rats by fundus Argon laser photocoagulation and evaluated by fundus fluorescein angiography (FAG). One day after CNV induction, the rats were treated with subconjunctival injection of recombinant adenovirus-vasostatin 20µl (1x10⁹ pfu) , recombinant adenovirus 20µl (1x10⁹ pfu), or PBS. The CNV extents were evaluated by FAG on day 21, 28, 35 and 42. The effect and safety ofsubconjunctival injection of recombinant adenovirus-vasostatin application on retina function were examined by electroretinography (ERG) on day 7. After subconjunctival injection of recombinant adenovirus-luciferase, the duration of adenovirus expression was evaluated by bioluminescence imaging at day 1 to 120.

Results: : FAG analysis revealed that the eyes received recombinant Ad-vasostatin (1x10⁹ pfu) exhibited significant decrease in CNV lesion areas compared with PBS treated or Ad-treated eyes on day 21, 28, 35 and 42 (P < 0.05). In ERG analysis, CNV lesion induced a prolonged latency in a- and b-wave. Subconjunctival injection of recombinant ad-vasostatin, but not recombinant adenovirus, significantly shorten the delayed a wave and b wave due to CNV (P < 0.05). Finally, there was no difference in ERG parameters between normal and recombinant Ad-vasostatin rats eyes, suggesting that the safety of VS48. After subconjunctival injection of recombinant Ad-luciferase, the bioluminescence image showed the viral ocular local expression until day 120, and systemic viral expression were not found.

Conclusions: : The present study demonstrates the potential of subconjunctival injection of recombinant Ad-vasostatin application to ameliorate choroidal neovascularization.

Keywords: choroid: neovascularization • gene transfer/gene therapy • age-related macular degeneration