Choroidal Neovascularization and Retinal Pigment Epithelium, and Laser Photocoagulation Treatment

1.用氪激光光凝法在猴眼黄斑区实验形成脉络膜新生血管和视网膜色素上皮，在自然病程中，脉络膜新生血管发生在光凝后1~2周，发展到3~4周，之后在5~8周自发消退。在退行性阶段，RPE以单细胞层的形式增殖到包膜上(封闭)。我们在PC前或PC后全身注射碘化钠(Na10_3)或玻璃体内注射少量的1-鸟氨酸盐酸盐对RPE造成损伤。碘化钠损伤RPE和感光细胞外段，鸟氨酸选择性损伤RPE。在PC前给予这些药物的患者中，CHNV根本没有发展。在Ey…在CHNV、CHNV发病后使用这些药物的ES更多地在半年内持续并生长，没有任何自发消退的迹象。这些结果表明，RPE细胞与CHNV的发展和消退有密切关系，1)迁移的RPE细胞可诱导CHN的生长，2)RPE的增殖对CHNV的消退起作用，3)受损的RPE未表现出这种作用。激光治疗实验性脉络膜新生血管的组织病理学研究激光光凝治疗实验性脉络膜新生血管(CHNV)后激光损伤的组织病理学过程。我们利用强氪激光PC和玻璃体内注射1-鸟氨酸盐酸盐的方法，在猴眼中制备了发育良好、持续时间长的CHNV。用橙色激光(590 Nm)治疗CHNV，经染料激光PC治疗后，部分病变的ChNV消失，皮损变干，而另一些病变，ChNV生长，皮损持续湿润。对这些PC病变进行组织病理学研究。光镜和电子显微镜检查发现，干性病变的视网膜下腔充满了增殖的RPE细胞，未见新生血管。在湿性病变处可见大量新生血管，并伴有视网膜下间隙的成纤维细胞样RPE细胞、成纤维细胞和巨噬细胞。这些结果表明，在激光治疗中，PC关闭CHNV是必要的，而PC不足会导致NV的进一步发展和视网膜下间隙的细胞增殖，导致治疗失败。较少

1. Choroidal Neovascularization and the Retinal Pigment EpitheliumChoroidal neovascularization (ChNV) was produced experimentally in the macular area in monkey eyes by krypton laser photocoagulation (PC).In natural course following PC, ChNV occurred in 1 or 2 weeks after PC, and developed in 3 to 4 weeks, thereafter ChNV regressed spontaneously in 5 to 8 weeks.In histological study, we found, at the developing stage of ChNV, immature ChNVs were usually accompanied with migrated retinal pigment epithelial cells (RPE). At the stage of regression, RPE have proliferated to envelope ChNV as a single cell layer (sealing off).We damaged RPE by systemic administration of sodium iodite (Na 10_3) pre or post PC, or intravitreal injection of a small amount of 1 Ornithine hydrochloride. Sodium iodite damaged RPE and the outer segment of the photoreceptors, and Ornithine damaged RPE selectively. In the eyes in which these drugs were administrated before PC, ChNV have not developed at all. In the ey … More es in which these drugs were administrated after development of ChNV, ChNV have lasted and grown in half a year without any evidence of spontaneous regression. Histologically, RPE have not shown proliferation and enveloping to ChNV in these eyes.These results showed RPE cells have close relations to development and regression of ChNV, 1) migrated RPE cells may induce growing of ChN, 2) proliferations of RPE play a role to regression of ChNV, 3) damaged RPE has not shown such a role.2. Histopathology of Laser Treatment for Experimental Choroidal NeovascularizationWe studied histopathological process of lasered lesion following laser photocoagulation (PC) for experimental choroidal neovascularization (Ch NV). We produced well-developed and long-lasting ChNVs in monkey eyes by means of intense Krypton laser PC and succeedingly intravitreal injection of 1-ornithine hydrochloride. Those ChNVs were treated by orange beam (590nm) of dye laser.After dye laser PC, clinically and fluoangiographically, in some lesions, ChNVs disappeared and the lesions became dry, however, the other lesions, ChNVs grew and the lesions lasted in wet condition. Histopathological studies were made for those PC lesions. Light and EM scopy revealed, at the dry lesions, subretinal space was filled with proliferated RPE cells and NVs were not found. At the wet lesions, new vessels were found numerously, accompanied with fibroblast-like RPE cells, fibroblast, and macrophages in subretinal space.These results showed in laser treatment, closure of ChNV is essentially necessary by PC, and insufficient PC induces further development of NV and cellular proliferation in the subretinal space, and causes failure of treatment. Less