Effect of circadian clock and claudin regulations on inulin-induced calcium absorption in the mouse intestinal tract

Bioscience of Microbiota, Food and Health

article

Kazuto SHIGA¹  Atsushi HARAGUCHI¹  Hiroyuki SASAKI¹  Yu TAHARA¹  Kanami ORIHARA¹  Shigenobu SHIBATA¹ 

[1] Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University;Graduate School of Biomedical and Health Sciences, Hiroshima University;School of Life Science and Technology, Tokyo Institute of Technology

关键词: circadian rhythm;    clock gene;    claudin;    tight junction;    prebiotics;    calcium absorption;   

DOI  :  10.12938/bmfh.2022-029

学科分类：生物科学（综合）

来源: Nihon Bifizusukin Senta / Japan Bifidus Foundation

【 摘 要 】

Dietary calcium supplementation has been shown to be an effective adjunct therapy in an inflammatory bowel disease model. Soluble dietary fiber reduces intestinal pH and is known to enhance calcium absorption. Although many circadian clock regulations of nutrient absorption in the intestinal tract have been reported, the effects of clock regulation on calcium absorption have yet to be understood. In this study, we investigated the timing of efficient calcium intake by measuring urinary calcium excretion in mice. The diurnal variations in channel-forming tight junctions (claudins) were detected in both the jejunum and ileum. Following 2 days of feeding with a Ca2+-free diet, Ca2+-containing diets with or without soluble fiber (inulin) were fed at specific timings, and urine was subsequently examined every 4 hr. There was an evident increase in urinary calcium concentration when the inulin diet was fed at the beginning of the resting period. The Claudin 2 (Cldn2) expression level also showed a significant day-night change, which seemed to be a mechanism for the increased calcium excretion after inulin intake. This diurnal rhythm and enhanced Cldn2 expression were abolished by disruption of the suprachiasmatic nucleus, the central clock in the hypothalamus. This study suggests that intestinal calcium absorption might be modulated by the circadian clock and that the intake of inulin is more effective at the beginning of the resting period in mice.

【 授权许可】

CC BY