Chuang Lan-Hsin, Hwang Yih-Shiou, Wang Nan-Kai, Chen Yen-Po, Liu Laura, Yeung Ling, Chen Kuan-Jen, Chen Tun-Lu, Wu Wei-Chi, Lai Chi-Chun
1 Department of Ophthalmology, Chang-Gung Memorial Hospital , Keelung, Taiwan .
J Ocul Pharmacol Ther. 2014 Oct;30(8):642-9. doi: 10.1089/jop.2013.0219. Epub 2014 Jun 20.
To compare the chorioretinal tissue response after different half-strength parameters of photodynamic therapy (PDT) in rabbits.
The study included 4 groups, and each group contained 4 animals. The full dose served as the control group: verteporfin (4 mg/kg) with 600 mW/cm(2) irradiance from a diode laser at 689 nm applied to the retina for 8 s. One parameter was changed to half-strength in the other 3 groups. The HLaser group received half-strength laser irradiance. The HTime group was exposed to photosensitization for half the time, and the HDose group received half the drug dose. Six laser spots were generated in each of the eyes of every rabbit and documented graphically. The lesions were examined on days 1, 7, and 42 after PDT treatment using color fundus imaging, fluorescein angiography (FA), and histopathology analysis.
PDT treatment in rabbits caused chorioretinal damage in all 4 groups. FA on day 1 showed that the use of half the laser irradiance, half the drug dose, or half the photosensitizing time tended to decrease the damage to the chorioretinal tissue in terms of the number of occlusions and the area of occlusion, but only the results from half the laser irradiance were significantly different. In addition, the HLaser and HDose groups showed significantly less apoptosis by TUNEL staining on day 1.
Among these PDT parameters, decreasing the laser irradiance by half showed the greatest decrease in chorioretinal damage in an experimental animal model.
比较不同半强度参数的光动力疗法（PDT）对兔脉络膜视网膜组织的反应。
本研究包括4组，每组4只动物。全剂量组作为对照组：用二极管激光器以689nm波长、600mW/cm²的辐照度将维替泊芬（4mg/kg）照射视网膜8秒。在其他3组中改变一个参数为半强度。HLaser组接受半强度激光辐照。HTime组接受一半时间的光敏化，HDose组接受一半药物剂量。在每只兔的每只眼睛中产生6个激光光斑，并进行图像记录。在PDT治疗后第1、7和42天，使用彩色眼底成像、荧光素血管造影（FA）和组织病理学分析检查病变。
兔的PDT治疗在所有4组中均导致脉络膜视网膜损伤。第1天的FA显示，使用一半的激光辐照度、一半的药物剂量或一半的光敏化时间，在闭塞数量和闭塞面积方面，脉络膜视网膜组织的损伤有减少趋势，但只有一半激光辐照度的结果有显著差异。此外，HLaser组和HDose组在第1天通过TUNEL染色显示凋亡明显较少。
在这些PDT参数中，将激光辐照度降低一半在实验动物模型中显示出脉络膜视网膜损伤减少最多。
