Nakao Ayaka, Hu Ailing, Yamaguchi Takuji, Tabuchi Masahiro, Ikarashi Yasushi, Kobayashi Hiroyuki
Department of Personalized Kampo Medicine, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
Department of Hospital Administration, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
Evid Based Complement Alternat Med. 2022 Sep 29;2022:4139812. doi: 10.1155/2022/4139812. eCollection 2022.
Inchinkoto (ICKT), a traditional herbal medicine that is often used as a hepatoprotective drug in Japan, has pharmacological properties that include antioxidant, anti-inflammatory, and choleretic actions. Genipin is a metabolite of geniposide and the most abundant ingredient of ICKT; furthermore, it is considered to be the active substance responsible for its pharmacological properties in the liver. Drugs with such pharmacological characteristics are expected to prevent intestinal barrier dysfunction, which causes inflammatory bowel diseases (IBDs). However, no studies have investigated the effects of ICKT on the intestinal epithelial barrier. Therefore, we investigated the activity of ICKT in intestinal tight junctions by using cultured Caco-2 cell monolayers. The action of the compound on tight junctions was examined by measuring transepithelial electrical resistance (TEER) and sodium fluorescein (Na-F) permeability in the presence or absence of lipopolysaccharide (LPS). Moreover, the expression of the tight junction protein claudin-1 was assessed by using immunofluorescent staining. ICKT and genipin increased TEER and decreased Na-F permeability, which was suggestive of enhanced intestinal epithelial barrier function. Moreover, they prevented the LPS-induced destruction of the barrier, i.e., a decrease in TEER and an increase in Na-F permeability. Immunofluorescence staining revealed a high claudin-1 expression level on the cell surface, whereas exposure to LPS downregulated claudin-1. In turn, ICKT and genipin prevented the LPS-mediated reduction of claudin-1. These results suggest that ICKT enhances intestinal epithelial barrier function by upregulating claudin-1. Furthermore, genipin contributed to these effects. ICKT may be a promising medicine for the prevention and treatment of diseases associated with intestinal barrier disruption, such as IBD, obesity, and metabolic disorders.
茵陈蒿汤（ICKT）是一种传统草药，在日本常被用作保肝药物，具有抗氧化、抗炎和利胆作用等药理特性。京尼平是栀子苷的代谢产物，也是ICKT中含量最丰富的成分；此外，它被认为是其在肝脏中发挥药理特性的活性物质。具有这种药理特性的药物有望预防导致炎症性肠病（IBD）的肠道屏障功能障碍。然而，尚无研究调查ICKT对肠上皮屏障的影响。因此，我们利用培养的Caco-2细胞单层研究了ICKT在肠紧密连接中的活性。通过在存在或不存在脂多糖（LPS）的情况下测量跨上皮电阻（TEER）和荧光素钠（Na-F）通透性，来检测该化合物对紧密连接的作用。此外，通过免疫荧光染色评估紧密连接蛋白claudin-1的表达。ICKT和京尼平增加了TEER并降低了Na-F通透性，这表明肠上皮屏障功能增强。此外，它们还预防了LPS诱导的屏障破坏，即TEER降低和Na-F通透性增加。免疫荧光染色显示细胞表面claudin-1表达水平较高，而暴露于LPS会下调claudin-1。反过来，ICKT和京尼平阻止了LPS介导的claudin-1减少。这些结果表明，ICKT通过上调claudin-1来增强肠上皮屏障功能。此外，京尼平促成了这些作用。ICKT可能是预防和治疗与肠道屏障破坏相关疾病（如IBD、肥胖和代谢紊乱）的一种有前景的药物。
