title: Small interference RNA targeting vascular endothelial growth factor gene effectively attenuates retinal neovascularization in mice model.
abstract: BACKGROUND
  The mechanism of retinal neovascularization is not understood completely. Many growth factors are involved in the process of retinal neovascularization, such as vascular endothelial growth factor (VEGF) and pigment epithelium-deprived factor (PEDF), which are the representatives of angiogenic and antiangiogenic molecules respectively. Oxygen induced retinopathy (OIR) is a useful model to investigate retinal neovascularization. The present study was conducted to investigate the feasibility of small interference RNA (siRNA) targeting VEGF gene in attenuating oxygen induced retinopathy (OIR) by regulating VEGF to PEDF ratio (VEGF/PEDF).
  
  
  METHODS
  In vitro, cultured EOMA cells were transfected with VEGF-siRNA (psi-HI(TM)/EGFP/VEGF siRNA) and Lipofectamine(TM) 2000 for 24, 48, and 72 hours, respectively. Expression of VEGF mRNA was evaluated by real time polymerase chain reaction (PCR) and the level of VEGF protein was analyzed by Western blotting. In vivo, OIR model mice were established, the mice (C57BL/6J) received an intra-vitreal injection of 1 µl of mixture of psi-HI(TM)/EGFP/VEGF siRNA and Lipofectamine 2000. Expressions of retinal VEGF and PEDF protein were measured by Western blotting, retinal neovascularization was observed by fluorescein angiography, and quantified.
  
  
  RESULTS
  In vitro psi-HI(TM)/EGFP/VEGF siRNA treatment significantly reduced VEGF mRNA and protein expression. In vivo, with decreased VEGF and VEGF-PEDF ratio, significant attenuation of neovascular tufts, avascular regions, tortuous, and dilated blood vessels were observed in the interfered animals.
  
  
  CONCLUSIONS
  VEGF plays an important role in OIR, and the transfection of VEGF-siRNA can effectively downregulate VEGF expression in vivo, accompanied by the downregulation of VEGF-PEDF ratio, and simultaneous attenuation of retinal neovascularization was also observed. These findings suggest that VEGF/PEDF may serve as a potential target in the treatment of retinal neovascularization and RNA interference targeting VEGF expression, which represents a possible therapeutic strategy.
authors.affiliation: Tianjin Eye Hospital; Tianjin Key Lab of Ophthalmology and Visual Science; Tianjin Eye Institute; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300020, China (Email: kongyc1942@hotmail.com).
authors.forename: Yi-chun
authors.initials: YC
authors.lastname: Kong
authors.forename: Bei
authors.initials: B
authors.lastname: Sun
authors.forename: Kan-xing
authors.initials: KX
authors.lastname: Zhao
authors.forename: Mei
authors.initials: M
authors.lastname: Han
authors.forename: Yu-chuan
authors.initials: YC
authors.lastname: Wang
mesh_terms: D000818:Animals; D005136:Eye Proteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D009414:Nerve Growth Factors / Q000032:analysis; D034741:RNA, Small Interfering / Q000235:genetics*; D015861:Retinal Neovascularization / Q000628:therapy*; D015843:Serpins / Q000032:analysis; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D005136:Eye Proteins; D009414:Nerve Growth Factors; D034741:RNA, Small Interfering; D015843:Serpins; D042461:Vascular Endothelial Growth Factor A; D000099174:Pigment Epithelium-Derived Factor