Miyamoto H, Kimura H, Yasukawa T, Honda Y, Tabata Y, Ikada Y, Sasai K, Ogura Y
Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Kyoto University, Japan.
Invest Ophthalmol Vis Sci. 1999 Jun;40(7):1496-502.
Radiation therapy has been used to treat choroidal neovascularization (CNV) in patients with age-related macular degeneration. The in vivo effect of applying focal x-ray irradiation to the eye of rabbits with experimental CNV was investigated.
CNV was induced in the rabbit eyes by subretinal implantation of gelatin hydrogel microspheres impregnated with basic fibroblast growth factor. Three weeks after implantation, 17 of 34 eyes with CNV lesions accompanied by fluorescein leakage were irradiated with a single dose of 20 Gy; the other 17 eyes were not irradiated and served as the controls. The eyes were examined before irradiation and 1, 2, and 4 weeks after irradiation, by indirect ophthalmoscopy and fluorescein angiography. The degree of a decreasing amount of fluorescein leakage from the CNV lesions after irradiation was graded using a computerized image analysis system and was compared in the irradiated and nonirradiated eyes. These eyes were also examined histologically and immunohistochemically.
Fluorescein leakage from the CNV lesions had significantly decreased in the eyes irradiated with 20 Gy compared with the control eyes, throughout the study period (P < 0.05). Histologic and immunohistochemical studies at 4 weeks after irradiation demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the irradiated eyes were less than those of the control eyes.
Focal x-ray irradiation at the ocular region effectively reduced experimental CNV activity. These results support the possibility that radiation therapy may be beneficial in treating CNV.
放射治疗已被用于治疗年龄相关性黄斑变性患者的脉络膜新生血管（CNV）。本研究调查了对实验性CNV兔眼进行局部X线照射的体内效应。
通过视网膜下植入含碱性成纤维细胞生长因子的明胶水凝胶微球在兔眼中诱导CNV。植入后3周，对34只伴有荧光素渗漏的CNV病变眼中的17只给予20 Gy的单次剂量照射；另外17只眼未接受照射作为对照。在照射前以及照射后1、2和4周，通过间接检眼镜检查和荧光素血管造影对眼睛进行检查。使用计算机图像分析系统对照射后CNV病变荧光素渗漏减少量的程度进行分级，并在照射组和未照射组眼中进行比较。对这些眼睛还进行了组织学和免疫组织化学检查。
在整个研究期间，与对照眼相比，接受20 Gy照射的眼中CNV病变的荧光素渗漏明显减少（P < 0.05）。照射后4周的组织学和免疫组织化学研究表明，照射眼视网膜下膜中的血管形成程度和血管内皮细胞数量均少于对照眼。
眼部区域的局部X线照射有效降低了实验性CNV的活性。这些结果支持放射治疗可能对治疗CNV有益的可能性。
