Zhu Hong, Alt Clemens, Webb Robert H, Melki Samir, Kochevar Irene E
*Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA; †Department of Ophthalmology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and ‡Boston Eye Group, Boston, MA.
Cornea. 2016 Sep;35(9):1234-41. doi: 10.1097/ICO.0000000000000916.
To evaluate crosslinking of cornea in vivo using green light activation of Rose Bengal (RGX) and assess potential damaging effects of the green light on retina and iris.
Corneas of Dutch belted rabbits were de-epithelialized, then stained with Rose Bengal and exposed to green light, or not further treated. Corneal stiffness was measured by uniaxial tensiometry. Re-epithelialization was assessed by fluorescein fluorescence. Keratocytes were counted on hematoxylin and eosin (H&E)-stained sections, and iris cell damage was assessed by lactate dehydrogenase staining. Thermal effects on the blood-retinal barrier (BRB) were assessed by fluorescein angiography and those on photoreceptors, retinal pigment epithelium (RPE), and choriocapillaris by light microscopy and transmission electron microscopy.
RGX (10-min irradiation; 150 J/cm) increased corneal stiffness 1.9-fold on day 1 (1.25 ± 0.21 vs. 2.38 ± 0.59 N/mm; P = 0.036) and 2.8-fold compared with controls on day 28 (1.70 ± 0.74 vs. 4.95 ± 1.86 N/mm; P = 0.003). Keratocytes decreased only in the anterior stroma on day 1 (24.0 ± 3.0 vs. 3.67 ± 4.73, P = 0.003) and recovered by day 28 (37.7 ± 8.9 vs. 34.5 ± 2.4, P = 0.51). Iris cells were not thermally damaged. No evidence of BRB breakdown was detected on days 1 or 28. Retina from RGX-treated eyes seemed normal with RPE cells showing intact nuclei shielded apically by melanosomes, morphologically intact photoreceptor outer segments, normal outer nuclear layer thickness, and choriocapillaris containing intact erythrocytes.
The substantial corneal stiffening produced by RGX together with the lack of significant effects on keratocytes and no evidence for retina or iris damage suggest that RGX-initiated corneal crosslinking may be a safe, rapid, and effective treatment.
利用孟加拉玫瑰红的绿光激活（RGX）评估体内角膜交联情况，并评估绿光对视网膜和虹膜的潜在损伤作用。
对荷兰带兔的角膜进行上皮去除，然后用孟加拉玫瑰红染色并暴露于绿光下，或不做进一步处理。通过单轴张力测定法测量角膜硬度。通过荧光素荧光评估再上皮化情况。在苏木精和伊红（H&E）染色切片上计数角膜细胞，并通过乳酸脱氢酶染色评估虹膜细胞损伤。通过荧光素血管造影评估对血视网膜屏障（BRB）的热效应，通过光学显微镜和透射电子显微镜评估对光感受器、视网膜色素上皮（RPE）和脉络膜毛细血管的热效应。
RGX（照射10分钟；150 J/cm）在第1天使角膜硬度增加1.9倍（1.25±0.21对2.38±0.59 N/mm；P = 0.036），与对照组相比，在第28天时增加2.8倍（1.70±0.74对4.95±1.86 N/mm；P = 0.003）。角膜细胞仅在第1天在前基质中减少（24.0±3.0对3.67±4.73，P = 0.003），并在第28天恢复（37.7±8.9对34.5±2.4，P = 0.51）。虹膜细胞未受到热损伤。在第1天或第28天未检测到BRB破坏的证据。RGX处理眼的视网膜看起来正常，RPE细胞显示核完整，顶端被黑素体屏蔽，光感受器外段形态完整，外核层厚度正常，脉络膜毛细血管含有完整的红细胞。
RGX产生的显著角膜硬化以及对角膜细胞无显著影响且无视网膜或虹膜损伤的证据表明，RGX引发的角膜交联可能是一种安全、快速且有效的治疗方法。
