Group of Structural Mechanics and Materials Modelling, Aragón Institute of Engineering Research (I3A), Mechanical Engineering Department, University of Zaragoza, María de Luna 3, 50018, Zaragoza, Spain.
Graefes Arch Clin Exp Ophthalmol. 2011 Aug;249(8):1223-7. doi: 10.1007/s00417-011-1674-0. Epub 2011 Apr 15.
To study the biomechanical effect of riboflavin-ultraviolet A irradiation (UVA)-induced collagen cross-linking (CXL) in porcine corneas using two different exposure times of 30 and 60 min.
Seventeen enucleated porcine eyes were divided into three groups: group A, six eyes without any treatment, group B, six eyes treated by UVA CXL for 30 min, and group C, five eyes treated by UVA CXL for 60 min. Riboflavin (vitamin B2) was used as a photosensitizer in both groups of treatment. Then, the stress-strain behavior of all the specimens was measured to compare the corneal biomechanical properties among the three groups. The Young's modulus E of the mean curve of each group shows the stiffness of treated and untreated tissue. The stress data necessary for stretches of 6, 8, and 12% were used to perform the statistical analysis of the values.
Group B (riboflavin-UVA-CXL, 30 min, E = 46 MPa) showed a stiffer behavior than group A (control, E = 29 MPa) . Group C (60 min CXL, E = 28 MPa) showed lower stiffness than group B and a similar mechanical behavior than group A. The statistical analysis of the stress-strain curves showed significant differences in the corneal response between group B and the control at the three values of stretch considered, 6, 8, and 12% (p = 0.025, p = 0.025 and p = 0.037, respectively) and between group B and group C (p = 0.028, p = 0.028, and p = 0.028). No statistically significant difference was found between group C and control (p = 0.855, p = 0.715, and p = 0.584).
The application of 30-min UVA CXL treatment with riboflavin increased stiffness of the porcine corneal tissue. A 60-min UVA-radiated tissue presents lower stiffness than the 30-min treated tissue, showing a similar biomechanical behavior than the untreated corneas. A prolongation of the UVA irradiation time may cause structural weakening of the porcine corneas.
使用两种不同的 30 分钟和 60 分钟照射时间，研究核黄素-紫外线 A 照射（UVA）诱导的胶原蛋白交联（CXL）对猪眼角膜的生物力学影响。
将 17 只去眼球猪眼分为三组：A 组 6 只眼不做任何处理，B 组 6 只眼用 UVA CXL 处理 30 分钟，C 组 5 只眼用 UVA CXL 处理 60 分钟。两组均使用核黄素（维生素 B2）作为光敏剂。然后，测量所有标本的应力-应变行为，比较三组角膜生物力学特性。每组平均曲线的杨氏模量 E 表示处理和未处理组织的硬度。拉伸 6%、8%和 12%所需的应力数据用于进行值的统计分析。
B 组（核黄素-UVA-CXL，30 分钟，E=46MPa）的行为比 A 组（对照组，E=29MPa）更硬。C 组（60 分钟 CXL，E=28MPa）的硬度低于 B 组，与 A 组的机械行为相似。在考虑的三种拉伸值（6%、8%和 12%）下，B 组与对照组之间的角膜反应的应力-应变曲线分析显示出显著差异（p=0.025，p=0.025 和 p=0.037），B 组与 C 组之间也存在显著差异（p=0.028，p=0.028 和 p=0.028）。C 组与对照组之间无统计学差异（p=0.855，p=0.715 和 p=0.584）。
应用核黄素 30 分钟 UVA CXL 处理可增加猪眼角膜组织的硬度。60 分钟 UVA 照射组织的硬度低于 30 分钟处理组织，其生物力学行为与未处理角膜相似。UVA 照射时间的延长可能导致猪眼角膜结构减弱。
