Water magnetic relaxation dispersion in biological systems: The contribution of proton exchange and implications for the noninvasive detection of cartilage degradation
Water magnetic relaxation dispersion in biological systems: The contribution of proton exchange and implications for the noninvasive detection of cartilage degradation
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DOI：
10.1073/pnas.221471898
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发表时间：
2001-10-23
影响因子：
11.1
通讯作者：
Leigh, JS
中科院分区：
文献类型：
--
作者：
Duvvuri, U;Goldberg, AD;Leigh, JS
磁弛豫已被广泛应用于生物组织的研究和表征。特别是，蛋白质溶液中水的旋转框架(T-1Rho)中的自旋晶格驰豫对大分子质量和组成是敏感的。然而，低频过程对水松弛的贡献的性质仍不清楚。我们通过研究水T-1 Rho在多肽溶液(N-14和N-15标记)、糖胺多聚糖溶液以及蛋白多糖降解前后的牛关节软骨样品中的分散情况来研究这个问题。我们在模型系统和组织中发现，在用于解释弛豫数据的模型的背景下，从NH和OH基团到水的氢交换主导着低频水尖端的分散。此外，低频弥散变化与关节软骨细胞外基质中蛋白多糖的丢失有关。这一发现对基质降解的非侵入性检测具有重要意义。
Magnetic relaxation has been used extensively to study and characterize biological tissues. In particular, spin-lattice relaxation in the rotating frame (T-1 rho) of water in protein solutions has been demonstrated to be sensitive to macromolecular weight and composition. However, the nature of the contribution from low frequency processes to water relaxation remains unclear. We have examined this problem by studying the water T-1 rho dispersion in peptide solutions (N-14- and N-15-labeled), glycosaminoglycan solutions, and samples of bovine articular cartilage before and after proteoglycan degradation. We find in model systems and tissue that hydrogen exchange from NH and OH groups to water dominates the low frequency water Tip dispersion, in the context of the model used to interpret the relaxation data. Further, low frequency dispersion changes are correlated with loss of proteoglycan from the extra-cellular matrix of articular cartilage. This finding has significance for the noninvasive detection of matrix degradation.