Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan.
Department of Electrical Engineering and Information Systems, The University of Tokyo, Tokyo 113-8656, Japan.
Cell Rep Methods. 2023 Jul 5;3(7):100519. doi: 10.1016/j.crmeth.2023.100519. eCollection 2023 Jul 24.
The biological activities of substances in the brain are shaped by their spatiotemporal dynamics in brain tissues, all of which are regulated by water dynamics. In contrast to solute dynamics, water dynamics have been poorly characterized, owing to the lack of appropriate analytical tools. To overcome this limitation, we apply stimulated Raman scattering multimodal multiphoton microscopy to live brain tissues. The microscopy system allows for the visualization of deuterated water, fluorescence-labeled solutes, and cellular structures at high spatiotemporal resolution, revealing that water moves faster than fluorescent molecules in brain tissues. Detailed analyses demonstrate that water, unlike solutes, diffuses homogeneously in brain tissues without differences between the intra- and the extracellular routes. Furthermore, we find that the water dynamics are steady during development and ischemia, when diffusions of solutes are severely affected. Thus, our approach reveals routes and uniquely robust properties of water diffusion in brain tissues.
大脑中物质的生物活性受其在脑组织中时空动态的影响，而所有这些动态都受水动力的调节。与溶质动态不同，由于缺乏适当的分析工具，水动力的特征描述一直很差。为了克服这一限制，我们将受激拉曼散射多模态多光子显微镜应用于活体脑组织。该显微镜系统能够以高时空分辨率可视化氘化水、荧光标记的溶质和细胞结构，揭示出水在脑组织中的移动速度快于荧光分子。详细分析表明，与溶质不同，水在脑组织中均匀扩散，不存在细胞内和细胞外途径的差异。此外，我们发现，在发展和缺血期间，当溶质扩散受到严重影响时，水动力学保持稳定。因此，我们的方法揭示了水在脑组织中的扩散途径和独特的稳健特性。
