Effect Of Proline Hydroxylases 2 On The Neonatal Mice By Oxygen-induced Retinopathy

Backgroud: Retinal neovascularization is a common pathology of the disease in retinal ischemia and hypoxia, including: diabetic retinopathy, retinal vein occlusion, retinopathy of premature children. retinal hypoxia causes vascular growth factors such as VEGF expression, and promots retinal endothelial cell division, proliferation and neovascularization. Currently, drug therapy for such diseases is mainly to inhibit VEGF, however,the treatment is not ideal. So it is necessary to find more effective ways to treat retinal vascular diseases in the upstream of VEGF.Objective: To observe the effects of proline hydroxylase 2 (PHD2) on oxygen-induced retinopathy (OIR) model.Methods: Forty C57BL/6J mice in postnatal day 7 were randomly divided into 4 groups: normal control group, hyperoxia group, 300mg/kg PHD2 inhibitor treatment group and 500mg/kg PHD2 inhibitor treatment group. The normal control group lived in normal circumstances and another three groups were exposed to (75±2)% oxygen for 5 days and then transfered to the normal air. After the end of the hyperoxia, two treatment groups were given different doses of inhibitor injected 1 time per day, continuous 5d. Hyperoxia group and normal control group were only given normal saline saline injection. P17 mice in each group were executed. After that, the eyeballs were collected, then made into Western blot, the flat-mounted retinas and tissue sections. After stained with hematoxylin and eosin (H-E), it was counted about endothelial cell nuclei breaking through the internal limiting membrane. Retinal a-SMA and VEGF protein were detected by immunohistochemical staining.Results: The PHD2 protein was expressed in retina by Western blot, hyperoxia group expression of PHD2 protein was significantly higher than the normal control group(P<0.05). Hyperoxia group in flat-mounted retina showed neovascularization and capillary perfusion loss in the central area; 300mg/kg and 500mg/kg treatment groups improved more significantly than hyperoxia group. The endothelial cell nuclei of H-E staining in the normal control group, the high-oxygen group, 300mg/kg treatment group and 500mg/kg treatment group were (0.6±0.84), (39.4±5.17), (15.8±1.93) and (6.3±1.57). difference of comparison among groups were statistically significant (P<0.05). Compare to hyperoxia group, a-SMA immunohistochemistry in 300mg/kg and 500mg/kg treatment groups were significantly higher; immunohistochemistry VEGF in high oxygen, 300mg/kg and 500mg/kg treatment groups significantly increased compared with the normal control group. 300mg/kg and 500mg/kg treatment groups compared with the hyperoxia group, VEGF expression was not significantly lowerConclusion: PHD2 expression in the retina and proline hydroxylase 2 inhibitor is effective in improving oxygen induced retinal neovascularization. It is a suggestion that PHD2 take part in the pathogenesis of retinal neovascularization.