Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2V4, Canada.
Osteoarthritis Cartilage. 2012 Sep;20(9):1004-10. doi: 10.1016/j.joca.2012.04.023. Epub 2012 May 8.
Cartilage cryopreservation requires optimal loading of protective solutes, most commonly dimethyl sulfoxide (DMSO), to maximize chondrocyte survival. Previously, diffusion models have been used to predict the distribution of solutes in tissue samples, but the accuracy of spatiotemporal predictions of these models have not been validated with empirical studies and remains unknown.
In this study, magnetic resonance spectroscopic imaging was used to measure the spatial and temporal changes in DMSO and water concentrations in porcine articular cartilage plugs, throughout 1 h of solute loading.
A custom NMR spectroscopic imaging pulse sequence provided water and DMSO concentration images with an in-plane spatial resolution of 135 μm and a temporal resolution of 150 s, repeated for 60 min throughout DMSO loading. Delayed gadolinium-enhanced magnetic resonance of cartilage (d-GEMRIC) imaging provided fixed charge density and spin-density imaging provided water density images prior to DMSO loading.
The measured spatial and temporal distribution of DMSO in three different samples was compared to independent predictions of Fick's law and the modified triphasic biomechanical model by Abazari et al. (2011) with the empirical data more closely agreeing with the triphasic model.
Dynamic NMR spectroscopic imaging can measure spatial and temporal changes in water and cryoprotectant concentrations in articular cartilage. The modified triphasic model predictions for the interstitial distribution of DMSO were confirmed and its advantage over the predictions by Fick's law model, which is commonly used in the literature of cryobiology, was demonstrated.
软骨冷冻保存需要将保护溶质（最常见的是二甲亚砜（DMSO））最佳负载以最大程度地提高软骨细胞存活率。以前，扩散模型已被用于预测组织样品中溶质的分布，但是这些模型的时空预测准确性尚未通过经验研究进行验证，并且仍然未知。
在这项研究中，磁共振波谱成像用于测量猪关节软骨塞中 DMSO 和水浓度在 1 小时溶质加载过程中的时空变化。
定制的 NMR 波谱成像脉冲序列提供了水和 DMSO 浓度图像，其平面内空间分辨率为 135μm，时间分辨率为 150s，在 DMSO 加载过程中重复 60 分钟。在 DMSO 加载之前，软骨的延迟钆增强磁共振成像（d-GEMRIC 成像）提供固定电荷密度，自旋密度成像提供水密度图像。
将三个不同样本中测量的 DMSO 的空间和时间分布与 Abazari 等人（2011 年）的菲克定律和改良三相生物力学模型的独立预测进行了比较，实验数据与三相模型更吻合。
动态 NMR 波谱成像可以测量关节软骨中水分和冷冻保护剂浓度的空间和时间变化。证实了改良三相模型对 DMSO 间质分布的预测，并证明了其优于文献中常用的菲克定律模型的预测。
