A sensitive analytical technique for visualizing small endogenous molecules simultaneously is of great significance for clearly elucidating metabolic mechanisms during pathological progression. In the present study, 1,5-naphthalenediamine (1,5-DAN) hydrochloride was prepared for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) of small molecules in liver, brain, and kidneys from mice. Furthermore, 1,5-DAN hydrochloride assisted LDI MSI of small molecules in brain tissue of rats subjected to middle cerebral artery occlusion (MCAO) was carried out to investigate the altered metabolic pathways and mechanisms underlying the development of ischemic brain damage. Our results suggested that the newly prepared matrix possessed brilliant features including low cost, strong ultraviolet absorption, high salt tolerance capacity, and fewer background signals especially in the low mass range (typically m/z < 500), which permitted us to visualize the spatial distribution of a broad range of small molecule metabolites including metal ions, amino acids, carboxylic acids, nucleotide derivatives, peptide, and lipids simultaneously. Nineteen endogenous metabolites involved in metabolic networks such as ATP metabolism, tricarboxylic acid (TCA) cycle, glutamate-glutamine cycle, and malate-aspartate shuttle, together with metal ions and phospholipids as well as antioxidants underwent relatively obvious changes after 24 h of MCAO. The results were highly consistent with the data obtained by MRM MS analysis. These findings highlighted the promising potential of the organic salt matrix for application in the field of biomedical research.

中文翻译：

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局部脑缺血后组织中小分子的1,5-二氨基萘盐酸盐辅助激光解吸/电离质谱成像

同时可视化小内源性分子的灵敏分析技术对于清楚阐明病理过程中的代谢机制具有重要意义。在本研究中，制备了1,5-萘二胺（1,5-DAN）盐酸盐，用于小鼠肝，脑和肾中小分子的基质辅助激光解吸/电离（MALDI）质谱成像（MSI）。此外，进行了1,5-DAN盐酸盐辅助的大脑中动脉闭塞（MCAO）大鼠脑组织中小分子LDI MSI的研究，探讨了缺血性脑损伤发生的改变的代谢途径和机制。我们的结果表明，新制备的基质具有低成本，强紫外线吸收，m / z <500），这使我们能够可视化同时显示多种小分子代谢物的空间分布，包括金属离子，氨基酸，羧酸，核苷酸衍生物，肽和脂质。参与代谢网络的19种内源性代谢物，例如ATP代谢，三羧酸（TCA）循环，谷氨酸-谷氨酰胺循环和苹果酸-天冬氨酸穿梭，以及金属离子和磷脂以及抗氧化剂，在MCAO 24小时后发生了相对明显的变化。结果与通过MRM MS分析获得的数据高度一致。这些发现突出了有机盐基质在生物医学研究领域中的应用前景。