Corneal Collagen Ordering After In Vivo Rose Bengal and Riboflavin Cross-Linking
Corneal Collagen Ordering After In Vivo Rose Bengal and Riboflavin Cross-Linking
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DOI：
10.1167/iovs.61.3.28
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发表时间：
2020-03-01
影响因子：
4.4
通讯作者：
Marcos, Susana
中科院分区：
文献类型：
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作者：
Germann, James A.;Martinez-Enriquez, Eduardo;Marcos, Susana
目的。光激活角膜胶原交联（CXL）通过启动基质蛋白之间的共价键形成增加角膜硬度。由于CXL依赖于光引发剂的扩散，因此CXL的效率随深度的变化而变化，这可能会影响基质胶原组织的程度。采用二次谐波显微镜（SHG）观察兔角膜CXL术后间质胶原组织随手术深度和时间的变化。用核黄素/紫外线辐射（UVX）或玫瑰/绿光（RGX）治疗兔角膜，并在CXL后1和2个月进行评估。使用特制的SHG扫描显微镜（350 μ m深度，225 × 225 μ m面部图像）通过中央角膜对胶原纤维进行成像。计算每个深度的顺序系数（OC），胶原组织的度量，和总SHG信号，并比较不同处理。RGX和UVX治疗后1个月OC值分别比未治疗组高27%和20%，2个月OC值分别比未治疗组高38%和33%。1个月和2个月时，RGX OC值比UVX OC值分别大3%和5%。在术后1个月和2个月，CXL角膜的SHG信号比未治疗的角膜高18%和26%，RGX和UVX分别高1%和10%。在CXL角膜中，OC的增加与胶原纤维组织的增加相对应。胶原组织的变化与报道的CXL后角膜硬度的时间变化平行，而且令人惊讶的是，在基质中比胶原交联硬化的区域更深。
PURPOSE. Photoactivated cornea collagen cross-linking (CXL) increases corneal stiffness by initiating formation of covalent bonds between stromal proteins. Because CXL depends on diffusion to distribute the photoinitiator, a gradient of CXL efficiency with depth is expected that may affect the degree of stromal collagen organization. We used second harmonic generation (SHG) microscopy to investigate the differences in stromal collagen organization in rabbit eyes after corneal CXL in vivo as a function of depth and time after surgery.METHODS. Rabbit corneas were treated in vivo with either riboflavin/UV radiation (UVX) or Rose Bengal/green light (RGX) and evaluated 1 and 2 months after CXL. Collagen fibers were imaged with a custom-built SHG scanning microscope through the central cornea (350 mu m depth, 225 x 225 mu m en face images). The order coefficient (OC), a metric for collagen organization, and total SHG signal were computed for each depth and compared between treatments.RESULTS. OC values of CXL-treated corneas were larger than untreated corneas by 27% and 20% after 1 month and 38% and 33% after 2 months for the RGX and UVX, respectively. RGX OC values were larger than UVX OC values by 3% and 5% at 1 and 2 months. The SHG signal was higher in CXL corneas than untreated corneas, both at 1 and 2 months after surgery, by 18% and 26% and 1% and 10% for RGX and UVX, respectively.CONCLUSIONS. Increased OC corresponded with increased collagen fiber organization in CXL corneas. Changes in collagen organization parallel reported temporal changes in cornea stiffness after CXL and also, surprisingly, are detected deeper in the stroma than the regions stiffened by collagen cross-links.