Joussen A M, Kruse F E, Otzel D, Holz F G, Debus J, Rohrschneider K, Völcker H E
Universitäts-Augenklinik Heidelberg.
Ophthalmologe. 1999 Apr;96(4):234-9. doi: 10.1007/s003470050398.
The clinical effect of ionidizing radiation on ocular neovascularizations is controversial not only because of the variety of treatment modalities. The aim of our study was to investigate an experimental model which allows to evaluate radiation parameters and to study the mechanism of the inhibitory effect on neoangiogenesis.
Corneal angiogenesis was induced by use of a micropocket assay in NZW rabbits. Pellets with 500 ng bFGF in 2% methylecellulose were implanted into the stroma 2.0 mm from the limbus. Initiation of vessel growth occurred on day 3. At this time radiation was performed with different doses (single dose of 15 to 30 Gy or fractionated 5 x 5 Gy) using a 6 MeV linear accelerator. Vascular growth was quantified.
Irradiation with a total dose of 25 Gy applied in a fractionated regimen or as single-dose irradiation on the day of surgery or on day 6 after surgery did not significantly reduce neovascular growth. In contrast, postoperative radiation therapy on day 3 was able to reduce the area of ingrowing vessels significantly (P < 0.01). In spite of the relatively high dose there were no significant side effects during the observation period of 8 weeks.
Our results show that single-dose radiation (> or = 25 Gy) is sufficient to inhibit the growth of corneal neovascularizations. With this model it might be possible to investigate parameters for therapy of ocular neovascularizations as well as the underlying mechanisms.
电离辐射对眼部新生血管形成的临床效果存在争议，这不仅是因为治疗方式多种多样。我们研究的目的是探究一种实验模型，该模型能够评估辐射参数并研究其对新生血管形成抑制作用的机制。
在新西兰白兔中采用微囊试验诱导角膜血管生成。将含有500 ng碱性成纤维细胞生长因子（bFGF）的2%甲基纤维素小球植入角膜缘2.0 mm处的基质层。血管生长在第3天开始。此时，使用6 MeV直线加速器以不同剂量（单次剂量15至30 Gy或分次5×5 Gy）进行辐射。对血管生长进行定量分析。
在手术当天或术后第6天采用分次方案或单次剂量照射，总剂量为25 Gy时，并未显著减少新生血管生长。相比之下，术后第3天进行放射治疗能够显著减少新生血管向内生长的面积（P < 0.01）。尽管剂量相对较高，但在8周的观察期内未出现明显副作用。
我们的结果表明，单次剂量辐射（≥25 Gy）足以抑制角膜新生血管的生长。利用该模型有可能研究眼部新生血管形成治疗的参数以及潜在机制。
