Enhancing Rose Bengal-Photosensitized Protein Crosslinking in the Cornea
Enhancing Rose Bengal-Photosensitized Protein Crosslinking in the Cornea
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DOI：
10.1167/iovs.19-26604
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发表时间：
2019-05-01
影响因子：
4.4
通讯作者：
Kochevar, Irene E.
中科院分区：
文献类型：
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作者：
Wertheimer, Christian M.;Elhardt, Carolin;Kochevar, Irene E.
目的。孟加拉玫瑰(RB)-光敏蛋白交联已被提出用于眼睛的几个应用。本研究确定了Rb光敏交联在角膜中的氧依赖和氧非依赖机制，以提高其治疗眼科的效率。方法：体外兔角膜用1 mM Rb染色，并在532 nm处照射。用分光光度法和线拉伸强度测试法对RB进行了光漂白，并在有氧和无氧的情况下进行了测试。叠氮化钠、D2O、精氨酸和抗坏血酸的影响被用来区分能量转移(形成单线态氧)和电子转移(形成自由基离子)的机制。结果：有氧时RB光漂白大于无氧时，D2O促进RB光漂白，叠氮部分抑制RB光漂白，提示RB光漂白为单线态氧途径。精氨酸和抗坏血酸增强了无氧光漂白，并伴随着吸收向更短波长的移动，这表明电子转移启动了Rb的光分解。空气中Rb光敏拉伸强度的增加被D2O增强，而被叠氮抑制。在无氧环境中，抗张强度的增加需要精氨酸，这与在没有精氨酸的空气中辐射所获得的结果相当，这表明了一种有效的电子转移途径。在80~120微米以下只有精氨酸存在时，才能观察到快速光漂白.这些结果表明，Rb通过单线态氧和电子转移两种机制光敏化角膜中的交联物，加入增强剂可提高这种处理的效率.
PURPOSE. Rose bengal (RB)-photosensitized protein crosslinking has been proposed for several applications in the eye. This study identifies oxygen-dependent and oxygen-independent mechanistic pathways in cornea for RB-photosensitized crosslinking to enhance its efficiency for ocular treatments.METHODS. Rabbit corneas ex vivo were stained with 1 mM RB and irradiated at 532 nm. RB photobleaching, measured by spectrophotometry and linear tensile strength testing, were performed with and without oxygen present. The effects of sodium azide, D2O, arginine, and ascorbate were used to discriminate between mechanisms involving energy transfer (forming singlet oxygen) and electron transfer (forming radical ions). The influence of corneal depth on RB photobleaching was determined using inclined corneal incisions.RESULTS. RB photobleaching was greater in the presence than the absence of oxygen, enhanced by D2O and partially inhibited by azide, indicating a singlet oxygen pathway. Photobleaching without oxygen was enhanced by arginine and ascorbate and accompanied by a shift in the absorption to shorter wavelengths, suggesting that electron transfer initiates RB photodecomposition. The RB-photosensitized tensile strength increase in air was enhanced by D2O and inhibited by azide. In an O-2-free environment, arginine was required for an increase in tensile strength, which matched that attained by irradiation in air without arginine, suggesting an efficient electron transfer pathway. Rapid photobleaching was observed below 80 to 120 mu m only when arginine was present.CONCLUSIONS. These results indicate that RB photosensitizes crosslinking in cornea by both singlet oxygen and electron transfer mechanisms and that adding enhancers may increase the efficiency of this treatment.