Laboratory for Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland; ELZA Institute, Dietikon, Switzerland; Faculty of Medicine, University of Geneva, Geneva, Switzerland.
ELZA Institute, Dietikon, Switzerland.
Exp Eye Res. 2022 Nov;224:109267. doi: 10.1016/j.exer.2022.109267. Epub 2022 Sep 24.
To evaluate whether repeated application of riboflavin during corneal cross-linking (CXL) has an impact on the corneal biomechanical strength in ex-vivo porcine corneas.
Laboratory investigation.
Sixty-six porcine corneas with intact epithelium were divided into three groups and analyzed. All corneas were pre-soaked with an iso-osmolar solution of 0.1% riboflavin in a phosphate-buffered saline (PBS) solution ("riboflavin solution"). Then, the corneas in Groups 1 and 2 were irradiated with a standard epi-off CXL (S-CXL) UV-A irradiation protocol (3 mW/cm for 30 min); while the corneas in Group 3 were not irradiated and served as control. During irradiation, Group 1 (CXL-PBS-Ribo) received repeated riboflavin solution application while corneas in Group 2 (CXL-PBS) received only repeated iso-osmolar PBS solution. Immediately after the procedure, 5-mm wide corneal strips were prepared, and elastic modulus was calculated to characterize biomechanical properties.
Significant differences in stress-strain extensiometry were found between two cross-linked groups with control group (P = 0.005 and 0.002, respectively). No significant difference was observed in the normalized stiffening effect between Groups 1 and 2 (P = 0.715).
The repeated application of riboflavin solution during UV-A irradiation does not affect the corneal biomechanical properties achieved with standard epi-off CXL. Riboflavin application during CXL may be omitted without altering the biomechanical stiffening induced by the procedure.
评估在角膜交联（CXL）过程中重复应用核黄素是否会对离体猪眼角膜的角膜生物力学强度产生影响。
实验室研究。
将 66 个完整上皮的猪眼角膜分为三组进行分析。所有角膜均先用磷酸盐缓冲盐水（PBS）溶液中的 0.1%核黄素等渗溶液（“核黄素溶液”）预浸泡。然后，第 1 组和第 2 组角膜采用标准的 epi-off CXL（S-CXL）UV-A 辐照方案（3 mW/cm 照射 30 分钟）进行辐照；而第 3 组角膜不进行辐照，作为对照。在辐照过程中，第 1 组（CXL-PBS-Ribo）接受重复的核黄素溶液应用，而第 2 组（CXL-PBS）仅接受重复的等渗 PBS 溶液。辐照后立即制备 5-mm 宽的角膜条，计算弹性模量以表征生物力学特性。
两组交联组与对照组之间的应变伸长计的应力-应变差异有统计学意义（P 值分别为 0.005 和 0.002）。第 1 组和第 2 组之间的归一化增硬效果无显著差异（P 值分别为 0.715 和 0.715）。
在 UV-A 照射过程中重复应用核黄素溶液不会影响标准 epi-off CXL 所达到的角膜生物力学特性。在 CXL 过程中省略核黄素的应用并不会改变该程序诱导的生物力学增硬效果。
