Abstract
Abstract: :
Purpose: To investigate the effect of Angiopoietin-1 (Ang-1) on the leakage of retinal neovascularization. Methods: Full length human Ang-1cDNA was amplified from total RNA of embryo heart tissue using RT-PCR protocol. Ang-1 cDNA was cloned into the eukaryotic expression vector pcDNA3.1(+). The resultant recombinant plasmid was transfected into a monkey kidney fibroblast cell-line COS-7 and human retinal pigment epithelium by a lipofectamine method. The Ang-1 expression was detected by immunocytochemistry. Retinal neovascularization was induced in Sprague-Dawley rat by photodynamic thrombosis. Ang-1 expression vector pcDNA3.1-Ang-1 with lipofectamine was injected either intravitreous or retrobulbar seven days after photodynamic thrombosis. The control group was treated with vector. seven days later, the retianl vascular leakage was quantified by Evans blue testing. Results: Full length RT-PCR amplified Ang-1 cDNA is exactly identical to human Ang-1 cDNA. Immunocytochemistry showed positive Ang-1 expression in COS-7 and RPE which have been transfected with recombinant plasmid pcDNA3.1-Ang1, but negative in those with vector. Of 24 eyes, fluorescein angiogram showed the neovascularization of the disc with leakage in 21 (87.5%) eyes 14 days after photodynamic thrombosis. The retinal vascular permeability of the eyes with neovascularization (10.19+/-4.73ng/mg) was significantly higher than normal eyes (3.75+/-2.97ng/mg). Seven days after in vivo liposome-mediated gene transfer, Evans blue testing revealed the intravitreous Ang-1 gene decreased retinal vascular leakage by 39% compared to control. Retrobulbar Ang-1 gene decreased retinal vascular leakage by 36.8%. Conclusions: Ang-1 gene transfer significantly reduces the retinal neovascular leakage in a retinal neovascularization model in rat. Ang-1 may be useful in the management of retinal vascular leakage.
Keywords: retinal neovascularization • gene transfer/gene therapy