Water in Sciatic Nerve Measured by Double-Quantum-Filtered NMR

点击翻译按钮获取中文摘要

The Aims of this project is 1) to reach an understanding of factors governing the NMR relaxation of water in peripheral nerve tissue and 2) to separate water compartmentation based on parameters of H-2 double-quantum relaxation to follow "order" structure of water and to use it to understand physiological processed in healthy and pathological tissues.1) Compartmentation of water in sciatic nerve of rats : Three compartments of ィイD12ィエD1HィイD22ィエD2O in anisotropic motion condition were detected by H-2 DQF NMR. The observed residual quadrupole splitting were ca. 480, 125 and 9 Hz at 24℃ which were assigned as ィイD12ィエD1HィイD22ィエD2O in endoneurium, epineurium, and axons respectively. The three DQF signals showed anisotropic diffusion, but only the axoplasm compartment represented restricted diffusion. From restricted diffusion of the axoplasm water, the inner-diameter of axon was estimated as 7.5 um.2) Development of flow-cell type NMR probe : We have made a flow-cell type of H-2 NMR probe. Using a glass capillary (1.5 mm inner diameter), perfusate of the sciatic could be switched within 10 sec which allows us to measure uni-directional water exchange between tissue compartments.3) Assessment of degeneration of sciatic nerve : Changes in water exchange and H-2 DQF relaxation parameters were measured on the Wallerian degeneration nerve. Water permeability increased and water structures in the 3 compartments degenerated by 1-2 weeks. It is possible to follow the degeneration process by H-2 DQF NMR.