Objective To observe the inhibitory effects of gene transfer of canstatin on retinal neovascularization in mice. Methods Fifty-six 7-day-old C57BL/6J mice were randomly divided into control group,oxygen-induced retinopathy (OIR) group, empty vector group and treated group,14 mices in each group. Except for the control group,the mice in the other groups were exposed to (75plusmn;2)% oxygen for 5 days and then back to the normal air to establish the model of OIR. On postnatal 12 day, the treated group was received intravitreal injection of canstatin pCMV-HA, while the empty vector group was received the same volume of empty plasmid.The changes of retinal vessels were observed by Evans blue angiography on postnatal 17 day. With parafin section which stained by hematoxylin and eosin, then the number of endotheliocyte nuclei breaking throuhgh the internal limiting membrane（ILM） was observed and counted by optical microscope.Results Retinal blood vessels distributed regularly in treated group compared with OIR group and empty vector group.The differences of the number of endotheliocyte nuclei breaking throuhgh ILM in treated group was significant compared with the other two groups（F=39.006，Plt;0.001).Conclusion The canstatin pCMV-HA can effectively inhibit the retinalneovascularization in OIR.
Objective To investigate the effects of recombinant adeno-associated virus type-2 (rAAV2) mediated delivery of pigment epitheliumderived factor (PEDF) on oxygen-induced retinal neovascularization (OIRNV) in mice. Methods A total of 22 C57/BL6 mice at the age of 3 days received intravitreal injections of 1 mu;l rAAV2-PEDF and rAAV2EGFP into the left eyes (experimental group) and the right eyes (control group). All mice were put into the oxygen box right after the injection to induce the OIRNV model.4 mice were sacrificed and PEDF protein in retina was measured by western blot at postnatal days 13 (P13). Twelve mice underwent retinal angiography with high molecular weight fluoresceindextran, and another 6 mice were sacrificed for retinal lectin immunohistochemistry staining at P17. Absolute and relative nonperfusion areas of retinal neovascularization were analyzed by Image-Pro Plus 5.1 software. Results The expression level of PEDF protein was higher in the experimental group than that in the control group.The absolute nonperfusion area was (0.96plusmn;0.22) mm2 in the experimental group and (1.96plusmn;0.34) mm2 in the control group; the difference between the two groups was significant（t=-8.554, P＜0.01）. The relative nonperfusion area was (8.64plusmn;1.52)% in the experimental group and (17.27plusmn;2.98)% in the control group with a significant difference between the two groups (t=-8.97, P＜0.01).The absolute area of retinal neovascularization was (0.37plusmn;0.11) mm2 in the experimental group which was obviously higher than (1.26plusmn;0.38) mm2 in the control group (t=-7.8, P＜0.01); the relative areas in experimental and control groups was (3.96plusmn;0.66)% and (11.45plusmn;2.06)%, respectively, whose difference is apparently(t=-8.51, P＜0.01).The areas of retina neovascularization were (0.11plusmn;0.003) mm2 and (0.41plusmn;0.02) mm2 in the experimental and control groups, respectively, and the difference between the two groups was significant（t=-5.14, P＜0.01）.Conclusions PEDF protein can stably express in the mice retina after rAAV2-PEDF transfetion. rAAV2-PEDF can decrease the retinal non-perfusion areas and inhibit the retinal neovascularization in OIRNV mice.
Objective To investigate the inhibitory effects of fms-like typrosine kinase receptor sFlt-1 on retinal neovascularization (RNV).Methods Recombinant lentivirus sFlt-1（2-3）and sFlt-1（2-4）expressing the sFlt-1 (2-3) and (2-4) immunoglobulinlike regions of sFlt-1 were constructed. 96 seven-day-old C57/6J mice were randomly divided into 4 groups with 24 mice in each group. Group 1: normal control; group 2: experimental control; group 3: sFlt-1（2-3）; group 4: sFlt-1（2-4）.The mice in group 2-4 were exposed to hyperoxia with （75plusmn;2）% O2 for 5 days and then returned to normoxia with 21% O2;the mice received an intravitreal injection with 1 mu;l virus of empty vector, sFlt-1（2-3）,or sFlt-1（2-4）,respectively. Five days later, all mice underwent perfusion fluorecein angiography and retinal wholemont was made to observe the changes of retinal vessels; retinal sections were stained by hematoxylin and eosin and RNV endothelium cell nucleus were counted; vascular endothelial growth factor(VEGF) and VEGF receptor-2 (KDR/Flk-1) protein were measured by Western blot.Results Seventeen days after birth, the retinal area of fluorescein leakage and RNV, RNV nucleus which breaking through inner limiting membrane in group 3 and 4 were smaller or less than that in group 2（P＜0.01）; while VEGF protein didnprime;t changed much （P＞0.05）the expression of KDR/Flk-1 decreased significantly (P＜0.01). Conclusion sFlt-1（2-3）and sFlt-1（2-4）can inhibit the formation of oxygen-induced RNV,the former virus has a better effect.
Retinal neovascularization is a complicated pathophysiological process as a result of imbalance between angiogenic and antiangiogenic factors. Correct understanding of the signaling pathways, exploring the critical factors involved in retinal angiogenesis, looking for new strategies by reconstructing the new vessels are helpful for knowing the mechanism of the occurrence and development of reitnal neovascularization, which would be good for preventing and treating retinal neovascularization diseases.