Department of Industrial Engineering, University of Padova, via Venezia 1, 35131, Padova, Italy.
Centre for Mechanics of Biological Materials, University of Padova, via Marzolo 9, 35131, Padova, Italy.
BMC Vet Res. 2021 Oct 28;17(1):340. doi: 10.1186/s12917-021-03050-1.
Cornea is a composite tissue exhibiting nonlinear and time-dependent mechanical properties. Corneal ulcers are one of the main pathologies that affect this tissue, disrupting its structural integrity and leading to impaired functions. In this study, uniaxial tensile and stress-relaxation tests are developed to evaluate stress-strain and time-dependent mechanical behaviour of porcine corneas.
The samples are split in two groups: some corneas are analysed in an unaltered state (healthy samples), while others are injured with alkaline solution to create an experimental ulcer (lesioned samples). Furthermore, within each group, corneas are examined in two conditions: few hours after the enucleation (fresh samples) or after 7 days in a specific culture medium for the tissue (cultured samples). Finally, another condition is added: corneas from all the groups undergo or not a cross-linking treatment. In both stress-strain and stress-relaxation tests, a weakening of the tissue is observed due to the imposed conditions (lesion, culture and treatment), represented by a lower stiffness and increased stress-relaxation.
Alkali-induced corneal stromal melting determines changes in the mechanical response that can be related to a damage at microstructural level. The results of the present study represent the basis for the investigation of traditional and innovative corneal therapies.
角膜是一种具有非线性和时变力学特性的复合组织。角膜溃疡是影响该组织的主要病变之一，破坏其结构完整性并导致功能受损。在这项研究中，进行了单轴拉伸和应力松弛测试，以评估猪眼角膜的应力-应变和时变力学行为。
将样本分为两组：一些角膜未经处理（健康样本），而另一些则用碱性溶液损伤以创建实验性溃疡（病变样本）。此外，在每组内，将角膜在两种条件下进行检查：摘出后数小时（新鲜样本）或在特定组织培养基中培养 7 天后（培养样本）。最后，还增加了一种条件：所有组的角膜都进行或不进行交联处理。在应力-应变和应力松弛测试中，由于施加的条件（损伤、培养和处理），组织的强度减弱，表现为刚度降低和应力松弛增加。
碱性诱导的角膜基质融化决定了机械响应的变化，这些变化可能与微观结构水平的损伤有关。本研究的结果为传统和创新的角膜治疗方法的研究提供了基础。
