Inhibitory effects of Genistein on hyperoxia-induced retinal neovascularization

Objective

To investigate the effect of Genistein, a tyrosinase inhibitor, on retinal neovascularization in mice.

Methods

Thirty-six 7-day-old C57BL/6J mice were randomly assigned into hyperoxia-induced group, Genistein group, DMSO group and normal control group.The mice in the hyperoxia-induced group, Genistein group and DMSO group were fed in a static chamber with the oxygen volume fraction (75±2)% for 5 days and then sent back to natural environment for 5 days to establish retinal neovascular models, and 1 μl Genistein diluted by 5% dimethyl sulfoxide (DMSO) (400 mg/L) and 1 μl DMSO were intravitreally injected in the 12-day-old mice of Genistein group and DMSO group, respectively.The mice in the normal control group were bred in natural environment.The fluorescence angiography was carried out in 17-day-old mice (2 mice in each group) to prepare the whole retinal flatmounts, and the morphology of retinal vessels was observed under the fluorescence microscope.The other mice in various groups were sacrificed and the retinas were collected.The expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in mRNA and protein levels were detected by real-time fluorescence quantitative PCR and Western blot, respectively.The use and care of the mice complied with regulations for the management of laboratory animals.

Results

Retinal vessels were normal in the mice of normal control group.In the mice of the hyperoxia-induced group and DMSO group, retinal vessels were tortuous, and neovacularization and non-perfusion areas were visible.In the Genistein group, retinal vessels were clearly visible, but non-perfusion areas were exhibited.The relative expression levels of VEGF mRNA in retinas were 0.64±0.25, 0.37±0.23, 0.03±0.02 and 0.04±0.02, and the relative expression levels of bFGF mRNA in retinas were 21.40±3.07, 17.22±2.63, 0.52±0.25 and 0.67±0.23, in the hyperoxia-induced group, DMSO group, Genistein group and normal control group, and the expressions of VEGF and bFGF in mRNA level in the hyperoxia-induced group and DMSO group were significantly higher than those in the Genistein group and normal control group (all at P<0.05). The protein expression levels of VEGF and bFGF were 1.01±0.05 and 0.97±0.06 in the hyperoxia-induced group, 1.06±0.07 and 1.03±0.08 in the DMSO group, 0.73±0.05 and 0.76±0.07 in the Genistein group, 0.52±0.05 and 0.56±0.05 in the normal control group.The expressions of VEGF and bFGF in protein level in the hyperoxia-induced group and DMSO group were significantly higher than those in the Genistein group and normal control group (all at P<0.05).

Conclusions

Genistein can inhibit hyperoxia-induced retinal neovascularization may be by down-regulating the expressions of VEGF and bFGF in retinas.

Angiogenesis inhibitors/pharmacology; Neovascularization, retinal; hyperoxia; Vascular endothelial growth factor; Fibroblast growth factor