Department of Industrial Engineering, University of Miami, Coral Gables, FL, USA; Max Biedermann Institute for Biomechanics at Mount Sinai Medical Center, Miami Beach, FL, USA.
Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA.
Osteoarthritis Cartilage. 2020 Mar;28(3):375-382. doi: 10.1016/j.joca.2019.12.006. Epub 2020 Jan 7.
To date, the pathophysiology of the meniscus has not been fully elucidated. Due to the tissue's limited vascularization, nutrients and other molecular signals spread through the extracellular matrix via diffusion or convection (interstitial fluid flow). Understanding transport mechanisms is crucial to elucidating meniscal pathophysiology, and to designing treatments for repair and restoration of the tissue. Similar to other fibrocartilaginous structures, meniscal morphology and composition may affect its diffusive properties. The objective of this study was to investigate the role of solute size, and tissue structure and composition on molecular diffusion in meniscus tissue.
Using a custom FRAP technique developed in our lab, we measured the direction-dependent diffusivity in human meniscus of six different molecular probes of size ranging from ∼300Da to 150,000Da. Diffusivity measurements were related to sample water content. SEM images were used to investigate collagen structure in relation to transport mechanisms.
Diffusivity was anisotropic, being significantly faster in the direction parallel to collagen fibers when compared the orthogonal direction. This was likely due to the unique structural organization of the tissue presenting pores aligned with the fibers, as observed in SEM images. Diffusion coefficients decreased as the molecular size increased, following the Ogston model. No significant correlations were found among diffusion coefficients and water content of the tissue.
This study provides new knowledge on the mechanisms of molecular transport in meniscal tissue. The reported results can be leveraged to further investigate tissue pathophysiology and to design treatments for tissue restoration or replacement.
迄今为止，半月板的病理生理学尚未得到充分阐明。由于组织的血管有限，营养物质和其他分子信号通过扩散或对流（间质液流）在细胞外基质中传播。了解传输机制对于阐明半月板病理生理学以及设计修复和组织重建的治疗方法至关重要。与其他纤维软骨结构类似，半月板的形态和组成可能会影响其扩散特性。本研究旨在探讨溶质大小、组织结构和组成对半月板组织中分子扩散的作用。
使用我们实验室开发的定制 FRAP 技术，我们测量了来自 6 种不同分子探针的大小范围从 ∼300Da 到 150,000Da 的人半月板的各向异性扩散率。扩散率测量结果与样品的含水量有关。SEM 图像用于研究与传输机制相关的胶原结构。
扩散率具有各向异性，与垂直方向相比，平行于胶原纤维的方向明显更快。这可能是由于组织的独特结构组织呈现出与纤维平行的孔，如 SEM 图像中观察到的那样。扩散系数随着分子尺寸的增加而减小，符合奥格斯顿模型。未发现扩散系数与组织含水量之间存在显著相关性。
本研究提供了半月板组织中分子传输机制的新知识。报告的结果可用于进一步研究组织病理生理学，并设计用于组织修复或替代的治疗方法。
