Study On The Pathogenesis Of Choroidal Neovascularization And The Measure Of Prevention And Cure

Objective: Study on the pathogenesis of CNV and research into the measure of prevention and cure.Method: l.The experimental eyes of 33 anesthetized BN rats received krypton red laser (647nm, 360mW, 50um, 0.05s) . FFA and ICGA examinations occurred just before euthanasia and tissue was processed for histopathology and transmission electron microscopy on days 3, 7, 14, 21, 28 and 56. 2. The experimental eyes of 20 anesthetized BN rats received krypton laser to induce CNV. FFA and ICGA examinations occurred just before euthanasia on days 3, 7, 21 and 28 . The tissue was processed for immunohistochemistry of PCNA, CD34, VEGF, FLK-1, bFGF and FGFR1. 3. The experimental eyes of 40 anesthetized BN rats received krypton laser to induce CNV. In the treatment group, suramin lml(30mg/kg ) was administered to 20 rats intraperitoneally immediately after laser (once 3 days) . The control rats received vehicle 1ml (0.9% NaCl) only. FFA and ICGAexaminations occurred just before euthanasia on days 3, 7, 21 and 28. The tissue was processed for histopathology and transmission electron microscopy, in situ hybridization of VEGFmRNA and bFGFmRNA, immunohistochemistry ofFLK-1 andFGFR1.Results: 1. CNV was firstly observed on day 7 post laser by FFA, ICGA, light microscopy and electron microscopy. The highest rate is 76.0% on day 21. The thickness of the laser-induced CNV was increased from days 7 to 21 (P<0.01) . 2. PCNA was observed most on day 3 after laser. The area and density of stained cells for PCNA decreased in retina from days 3 to 21(P<0.01). The area fraction score of CNV for PCNA decreased from days 7 to 28(P<0.01). CD34 was mainly observed in the vascular of retina and choroid. The area and density of stained cells of CNV for CD34 increased from days 7 to 21(P<0.01). VEGF was observed in the vascular endothelial cells, the ganglion cells, the inner nuclear layers and the RPE cells in normal retina and the vascular endothelial cells of normal choroid of BN rat. The area and density of stained cells for VEGF decreased in retina after 3 days and increased in CNV after 7 days (P<0.01). They didn't significantly change after 21 days (P>0.05) . FLK-1 was detected inthe vascular endothelial cells, the ganglion cells of normal retina and the vascular endothelial cells of choroid. The level of expression in the CNV increased from days 7 to 21 (P<0.01). bFGF was observed in the ganglion cells, the inner nuclear layers and the RPE cells in normal retina of BN rat. FGFR1 was detected in the ganglion cells, the inner nuclear layers and choroid of normal eye. The area and density of stained cells for bFGF and FGFR1 decreased in retina after 3 days and increased in CNV after 7 days (P<0.01). They didn't significantly change after 21 days (P>0.05). 3. There aren't leakage of fluorescein and CNV stained with ICG at the laser lesions in the suramin treatment group. The most thickness of CNV is (25.28+6.56)um. CNV was firstly observed on day 7 post laser by FFA, ICGA, light microscopy and electron microscopy in the control group. The most thickness of CNV is (64.04?.44)um. The thickness of CNV in the suramin treatment group was significantly miner than it of the control group on days 7, 21and28 (P<0.01) . The area and density of stained cells for VEGFmRNA, FLK-1, bFGFmRNA and FGFR1 in CNV were significantly reduced in the suramin treatment group (P<0.01) . The area fraction score of stained cells of CNV hasn't significant changebetween the two groups from days 7 to 28 (P>0.05 ) .Conclusion: Krypton laser photocoagulation can be successfully used to produce CNV experimental model in the BN rat. The method is easy. CNV forms fast and lasts long. The rate is high. It can be used to imitate CNV of AMD for research. VEGF or bFGF gathered to the capillary of choroid and combined with its receptor(FLK-l or FGFR1). They mediated the differentiation of endothelial cells and the formation of CNV. The inhibitory effect of suramin to CNV is that suramin can block VEGF and bFGF to combine with FLK-1 and FGFR1 effec...