Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama-shi, Japan.
Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan.
Genes Cells. 2020 Apr;25(4):257-269. doi: 10.1111/gtc.12755. Epub 2020 Feb 27.
Most physiological changes follow a daily cycle in animals because their circadian rhythm is adjusted to and synchronized with sunlight. In particular, the circadian rhythm affects liver functions, including pharmacokinetics and metabolism. The influence of circadian rhythm has not been included in hepatotoxicity assays used in drug discovery and development. In this study, the contribution of circadian rhythm was investigated in acetaminophen-induced hepatotoxicity in mice and primary cultured hepatocytes. Hepatotoxicity was induced via the intraperitoneal administration of acetaminophen to a greater extent at night than during the day in mice. The sensitivity of acetaminophen-induced hepatotoxicity was consistent with the expression levels of acetaminophen-metabolizing enzyme and circadian genes. The host-derived circadian rhythm was still evident in the primary cultured hepatocytes within a day after their isolation from the liver. Primary cultured hepatocytes isolated at night were significantly more sensitive to acetaminophen than those isolated during the day. The sensitivity toward acetaminophen-induced hepatotoxicity depended on the circadian rhythm of the expression of acetaminophen-metabolizing genes and intracellular glutathione levels in primary cultured hepatocytes. These results obtained from cultured cells correspond to those in mice, suggesting that the timing of hepatocyte isolation is important when investigating drug metabolism and toxicity tests in culture.
大多数生理变化在动物中遵循每日周期，因为它们的昼夜节律与阳光同步并进行调整。特别是，昼夜节律会影响肝脏功能，包括药代动力学和新陈代谢。昼夜节律的影响尚未包含在药物发现和开发中使用的肝毒性检测中。在这项研究中，研究了昼夜节律在小鼠和原代培养肝细胞中对乙酰氨基酚诱导的肝毒性中的作用。与白天相比，夜间通过腹腔内给予对乙酰氨基酚在小鼠中引起更严重的肝毒性。对乙酰氨基酚诱导的肝毒性的敏感性与对乙酰氨基酚代谢酶和昼夜节律基因的表达水平一致。从肝脏分离后的一天内，原代培养的肝细胞中仍存在宿主来源的昼夜节律。与白天分离的原代培养肝细胞相比，夜间分离的原代培养肝细胞对乙酰氨基酚更为敏感。对乙酰氨基酚诱导的肝毒性的敏感性取决于原代培养肝细胞中对乙酰氨基酚代谢基因表达和细胞内谷胱甘肽水平的昼夜节律。从培养细胞中获得的这些结果与小鼠的结果相对应，表明在培养中研究药物代谢和毒性试验时，分离肝细胞的时间很重要。
