Preretinal Neovascularization by Laser-induced Thrombosis in Albino Rats and Inhibition of Neovascularization by Genistein

ABSTRACT

PURPOSE: To determine the effect of genistein, an inhibitor of protein tyrosine kinase, on preretinal neovascularization through the quantification of retinal neovascularization using image analyzer in an experimental rat model. METHODS: In 36 eyes of 36 rats, retinal vein occlusion was induced by photodynamic therapy with an argon green laser and systemic injection of rose bengal (40 mg/kg). The development and progression of retinal neovascularization was followed weekly by fluorescein angiography. Seven rats were sacrificed each week, after which two eyes were prepared with H and E staining for histologic examination, and five were prepared as a control group using ADPase staining for neovascularization analysis. In the remaining fifteen eyes, retinal vein occlusion was also induced using the same method. Immediately after vein occlusion, 4.0 mg of genistein dissolved in dimethyl sulfoxide (DMSO) was injected intraperitoneally twice a day for the first 7 days. Five rats were sacrificed each week and stained with ADPase. After ADPase staining, those samples with evidence of neovascularization were quantified using an image analyzer. RESULTS: No retinal neovasularizaion was found at the end of the first week. The size of retinal neovascularization for the five eyes sacrificed at the end of week 2 and 3 were 6.53+/-2.11 mm2 and 3.77+/-3.51 mm2 in the control group, and 2.22+/-1.01 mm2 and 1.64+/-0.88 mm2 in the genistein treatment group, respectively. Retinal neovascularization was successfully suppressed until two weeks after laser treatment by genistein in this rat neovascularization model. CONCLUSIONS: Genistein may be a useful treatment modality to suppress retinal neovascularization complicated with retinal ischemic injury.