Yajima Yuhei, Okuno Alato, Nakamura Isamu, Miyazaki Teruo, Honda Akira, Toyoda Atsushi
Department of Food and Life Sciences, College of Agriculture, Ibaraki University, Ami-machi, Ibaraki, Japan.
Department of Health and Nutrition, Faculty of Human Design, Shibata Gakuen University, Hirosaki-city, Aomori, Japan.
Int J Tryptophan Res. 2022 Jan 4;15:11786469211066285. doi: 10.1177/11786469211066285. eCollection 2022.
The kynurenine (Kyn) pathway plays crucial roles in several inflammation-induced disorders such as depression. In this study, we measured Kyn and other related molecules in the blood plasma, brain, and urine of male C57BL/6J mice (B6) fed non-purified (MF) and semi-purified (AIN-93G and AIN-93M) standard rodent diets. Mice fed MF had increased plasma Kyn levels compared with those on AIN93-based diets, as well as decreased hippocampal Kyn levels compared with those fed AIN-93G. Previous studies showed that branched chain amino acids (BCAAs) suppress peripheral blood Kyn transportation to the brain, but plasma BCAA levels were not significantly different between the diet groups in our study. Urine metabolome analysis revealed that feed ingredients affected the excretion of many metabolites, and MF-fed mice had elevated excretion of kynurenic and quinolinic acids, pivotal metabolites in the Kyn pathway. Collectively, the level of critical metabolites in the Kyn pathway in the central and peripheral tissues was strongly affected by feed ingredients. Therefore, feed selection is a critical factor to ensure the reproducibility of experimental data in studies involving rodent models.
犬尿氨酸（Kyn）途径在多种炎症诱导的疾病（如抑郁症）中发挥着关键作用。在本研究中，我们测量了喂食非纯化（MF）和半纯化（AIN-93G和AIN-93M）标准啮齿动物饲料的雄性C57BL/6J小鼠（B6）血浆、大脑和尿液中的犬尿氨酸及其他相关分子。与喂食基于AIN93饲料的小鼠相比，喂食MF的小鼠血浆犬尿氨酸水平升高，与喂食AIN-93G的小鼠相比，其海马体中的犬尿氨酸水平降低。先前的研究表明，支链氨基酸（BCAAs）会抑制外周血犬尿氨酸向大脑的转运，但在我们的研究中，不同饲料组之间的血浆BCAA水平并无显著差异。尿液代谢组分析显示，饲料成分会影响许多代谢物的排泄，喂食MF的小鼠犬尿酸和喹啉酸（犬尿氨酸途径中的关键代谢物）的排泄量有所增加。总体而言，饲料成分会强烈影响中枢和外周组织中犬尿氨酸途径关键代谢物的水平。因此，在涉及啮齿动物模型的研究中，饲料选择是确保实验数据可重复性的关键因素。
