Rangchian Aysan, Hubschman Jean-Pierre, Kavehpour H Pirouz
Department of Bioengineering, University of California, Los Angeles, United States; Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, United States.
Retina Division, Stein Eye Institute, University of California, Los Angeles, United States.
J Biomech. 2020 Aug 26;109:109921. doi: 10.1016/j.jbiomech.2020.109921. Epub 2020 Jul 5.
The viscoelastic behavior of vitreous gel is due to the presence of biopolymers in its structure. Fluid properties of the vitreous is mainly the result of interactions between the characteristics of collagen type II and Hyaluronic Acid networks. Having a better understanding of the structure of each component and their changes during aging and various diseases such as diabetes can lead to better monitoring and treatment options. We study the effects of collagenase type II on 44 samples of porcine vitreous using an in situ rheological experiment in comparison with 18 eyes in a control group injected with Phosphate Buffered Saline Solution. We analyze the behavior of each component over time in both groups. We focus on the changes of viscosity and elasticity of the collagen network within the vitreous. The results of the analysis in this study show that the changes in the fluid properties of the vitreous after collagenase injection is driven by the structural alterations of the collagen network. Creep compliance values of the collagen network are significantly higher in the first group compared to the control group one hour and twenty-four hours after the injection. In contrast, creep compliance of the HA network shows no statistically significant change one hour after the injection in both groups. The results of the reported analysis of individual components in this study support the previous findings on the alterations within the vitreous structure in its entirety.
玻璃体凝胶的粘弹性行为归因于其结构中生物聚合物的存在。玻璃体的流体特性主要是II型胶原蛋白和透明质酸网络特性之间相互作用的结果。更好地了解每个成分的结构及其在衰老过程中以及诸如糖尿病等各种疾病中的变化，有助于实现更好的监测和治疗方案。我们使用原位流变学实验研究了II型胶原酶对44个猪玻璃体样本的影响，并与注射磷酸盐缓冲盐水溶液的18只对照组眼睛进行了比较。我们分析了两组中各成分随时间的行为。我们重点关注玻璃体内胶原网络的粘度和弹性变化。本研究的分析结果表明，注射胶原酶后玻璃体流体特性的变化是由胶原网络的结构改变驱动的。注射后一小时和二十四小时，第一组胶原网络的蠕变柔量值显著高于对照组。相比之下，两组注射后一小时HA网络的蠕变柔量均无统计学显著变化。本研究中对各个成分的分析结果支持了此前关于玻璃体结构整体变化的研究发现。
