Thaler Sebastian, Haritoglou Christos, Choragiewicz Tomasz J, Messias Andre, Baryluk Aneta, May C Albrecht, Rejdak Robert, Fiedorowicz Michal, Zrenner Eberhart, Schuettauf Frank
Centre for Ophthalmology, Division of Experimental Ophthalmology, University of Tübingen, Röntgenweg 11, Tübingen, Germany.
Invest Ophthalmol Vis Sci. 2008 May;49(5):2120-6. doi: 10.1167/iovs.07-1476.
To investigate the intraocular effect of rhodamine 6G (R6G) on retinal structures and function in an in vivo rat model and to develop an in vivo method for accurate evaluation of new dyes for intraocular surgery.
R6G in physiologic saline solution (PSS) was injected into the vitreous of adult Brown Norway rats at concentrations of 0.0002%, 0.002%, 0.02%, 0.2%, and 0.5%. Control animals received only PSS. Retinal toxicity was assessed by retinal ganglion cell (RGC) counts, light microscopy 7 days later, photopic electroretinography (ERG), and measurement of scotopic sensitivity and recovery of dark adaptation 48 hours and 7 days after intravitreous injection.
R6G at concentrations of 0.2% and 0.5% led to a dose-dependent loss of RGC. The most significant loss occurred at 0.5%. Lower concentrations (0.0002%, 0.002%, and 0.02%) produced no statistically significant retinal ganglion cell loss. Analysis of the eyes by light microscopy showed no structural changes in the central retina, although injections of 0.5% R6G were followed by impressive degenerative changes adjacent to the injection sites. ERGs showed no effects of the highest R6G concentration on rods, kinetics of rhodopsin recovery after bleaching, or cone-driven responses.
R6G can be safely injected in doses of up to 0.02% in rats, but has a toxic effect on retinal ganglion cells at higher concentrations. Accumulation of R6G may be a problem at higher concentrations, particularly at the injection site.
在体内大鼠模型中研究若丹明6G（R6G）对视网膜结构和功能的眼内效应，并开发一种用于准确评估眼内手术新染料的体内方法。
将生理盐溶液（PSS）中的R6G以0.0002%、0.002%、0.02%、0.2%和0.5%的浓度注入成年棕色挪威大鼠的玻璃体。对照动物仅接受PSS。7天后通过视网膜神经节细胞（RGC）计数、光学显微镜检查、明视视网膜电图（ERG）以及在玻璃体内注射后48小时和7天测量暗视敏感度和暗适应恢复情况来评估视网膜毒性。
浓度为0.2%和0.5%的R6G导致RGC呈剂量依赖性损失。最显著的损失发生在0.5%。较低浓度（0.0002%、0.002%和0.02%）未产生统计学上显著的视网膜神经节细胞损失。光学显微镜检查眼睛显示中央视网膜无结构变化，尽管注射0.5% R6G后注射部位附近出现明显的退行性变化。ERG显示最高R6G浓度对视杆细胞、漂白后视紫红质恢复动力学或视锥细胞驱动反应无影响。
在大鼠中，R6G以高达0.02%的剂量注射是安全的，但浓度较高时对视网膜神经节细胞有毒性作用。在较高浓度下，尤其是在注射部位，R6G的蓄积可能是一个问题。
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