The Effect Of Genistein On The Expression Of Hypoxia Inducible Factor-1 And Interleukin-8 In Human Retinal Pigment Epithelium Cell

Retinal neovascularization is the major character of various ocular diseases including diabetic retinopathy, hypertensive retinopathy and retinal vein occlusion and is one of the vital causes of blindness. The same character of the retinal neovascularization is pathophysiological dysfunction associated with vascular complications of retinopathy.Genistein (4',5,7-trihydroxyisoflavone), the isoflavone of greatest interest in soy protein, has a wide variety of pharmacological effects on chemoprevention of breast and prostate cancers, prevention and treatment of cardiovascular disease and many other chronic diseases. Recently, it has reported that genistein could inhibit cornea neovascularization in vivo. In previous research, we also found genistein could dose-dependently inhibit the numbers of nuclei protruding above the inner limiting membrane in a mouse model of oxygen-induced retinopathy. However, the mechanism of action of genistein on retinal neovascularization is still poor understood.Human retinal pigment epithelium (RPE) and underlying Bruch's membrane form the outermost layer of the blood-retina barrier. One of the major roles of human RPE cells in ocular diseases is to express various cytokines and growth factors. Many studies have suggested that hypoxia inducible factor-1 (HIF-1) and interleukin-8 (IL-8) might play a critical role in the pathogenesis of retinal neovascularization.Genistein has a wide variety of pharmacological effects on chemoprevention of breast and prostate cancers, prevention and treatmentof cardiovascular disease and many other chronic diseases. However, the protective effects of genistein on human RPE are still not clear. Using cultured human RPE cells injured by KCl and CoCl2, the protective effects of genistein on human RPE was studied. The cells viability was measured by MTT assay and morphological changes of the cells were recorded. The results showed that KCl could significantly decrease the survival rate of RPE cells at 12h. Gen markedly increased the survival rate in a concentration-dependent manner. RPE cells presented progressively destruction of cell membrane 2h after 200 mmol/L KCl treatment and pycnosis of cell nuclear after 4h. After 8h pyknosis and batt-liked cell membrane could be seen and only pyknosis could be observed 12h later. These changes could be inhibited by 200 umol/L genistein. C0CI2 could also inhibit the survival rate of RPE cells and genistein could concentration-dependently elevate the survival rate. No significant morphological changes of RPE cells induced by C0CI2 were found.In order to explore the possible mechanism of inhibitive effect of genistein on retinal neovascularization, the time-dependent changes of HIF-la expression induced by hypoxia and CoCl2 treatment and the effects of genistein on the level of HIF-la expression in human RPE cells were examined. HIF-la expression was judged by relative fluorescence using a confocal scanning laser microscope coupled to a computer, determined. The results showed that hypoxia could markedly increase the expression of HIF-1 a. After pretreatment with genistein (50, 100, 200 jumol/L), the hypoxia-evoked HIF-la expression was concentration-dependently inhibited. CoCl2 treatment could also significantly elevate the level of HIF-la expression. Genistein 50, 100, 200 umol/L could also suppress HIF-la expression in a concentration-dependent manner. In addition, we determined the effects...