Feng Yuan, Li Yanwu, Zhou Di, Li Bingxin, Chen Gang, Li Ning
School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang 110016, China.
Pi-Wei Institute, Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, 510405, China.
Phytomedicine. 2022 Jan;94:153836. doi: 10.1016/j.phymed.2021.153836. Epub 2021 Oct 30.
The application/abuse of antibiotics can cause antibiotic-induced intestinal injury (AIJ), a typical clinical issue that disturbs intestinal homeostasis. However, the underlying post-transcriptional mechanism of AIJ remains unknown. Glycyrrhetinic acid (GA) is one of the main components of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Batalin (Fabaceae), and findings of our previous study showed that GA can maintain intestinal homeostasis post-transcriptionally through the RNA-binding protein human antigen R (HuR).
This study aimed to elucidate the role of HuR in AIJ and the protective effects of GA on AIJ.
Clindamycin hydrochloride was used to clarify the effect of the antibiotic on the intestinal epithelium. Intestinal epithelium cell-6 (IEC-6) and Caco2 cells were used to demonstrate the in vitro effects of the antibiotic and GA on intestinal cells. HuR plasmid and siRNA were used to overexpress or silence HuR in vitro. SD rats were induced by using clindamycin hydrochloride capsules (250 mg/kg i.g.) for 7 consecutive days to construct the in vivo AIJ model. Rats of the AIJ model group were administrated GA (10 and 20 mg/kg i.g.) for 7 days, and subsequently, the protective effect of GA on the intestinal epithelium was evaluated.
In vitro results showed that the antibiotic (150-500 μM) suppressed proliferation, induced a delay in restitution after wounding, and caused cell cycle arrest at the G0/G1 phase in IEC-6 and Caco-2 cells. Moreover, the expression levels of HuR and its downstream gene, occludin and cyclin D1, decreased after treatment with the antibiotic (500 μM). Overexpression of HuR and GA (10 and 20 μM) reversed the antibiotic-induced inhibition of proliferation and G0/G1 phase arrest, and the antibiotic-induced decrease in HuR, occludin, and cyclin D1 expression was reversed after GA treatment (10 and 20 μM) in IEC-6 cells. In vivo results revealed the antibiotic-induced epithelial injury of both the small intestines (shortened and spared mucosa) and the large intestines (injured/deformed glands, reduced number of cup cells, and evident inflammatory cell infiltration), all of which were ameliorated after GA treatment (10 and 20 μM).
Antibiotics induce intestinal epithelial injury through HuR, and GA can exert a protective effect on AIJ by restoring HuR levels.
抗生素的应用/滥用可导致抗生素诱导的肠道损伤（AIJ），这是一个干扰肠道稳态的典型临床问题。然而，AIJ潜在的转录后机制仍不清楚。甘草次酸（GA）是乌拉尔甘草和胀果甘草（豆科）的主要成分之一，我们之前的研究结果表明，GA可通过RNA结合蛋白人抗原R（HuR）在转录后维持肠道稳态。
本研究旨在阐明HuR在AIJ中的作用以及GA对AIJ的保护作用。
使用盐酸克林霉素来阐明抗生素对肠上皮的影响。采用肠上皮细胞-6（IEC-6）和Caco2细胞来证明抗生素和GA对肠道细胞的体外作用。使用HuR质粒和小干扰RNA（siRNA）在体外过表达或沉默HuR。通过连续7天给SD大鼠灌胃盐酸克林霉素胶囊（250mg/kg）来构建体内AIJ模型。给AIJ模型组大鼠灌胃GA（10和20mg/kg）7天，随后评估GA对肠上皮的保护作用。
体外实验结果表明，抗生素（150 - 500μM）抑制IEC-6和Caco-2细胞的增殖，导致伤口愈合延迟，并使细胞周期停滞在G0/G1期。此外，用抗生素（500μM）处理后，HuR及其下游基因闭合蛋白和细胞周期蛋白D1的表达水平降低。在IEC-6细胞中，HuR的过表达以及GA（10和20μM）可逆转抗生素诱导的增殖抑制和G0/G1期停滞，并且GA处理（10和20μM）后可逆转抗生素诱导的HuR、闭合蛋白和细胞周期蛋白D1表达的降低。体内实验结果显示，抗生素可导致小肠（黏膜缩短和缺失）和大肠（腺体损伤/变形、杯状细胞数量减少以及明显的炎性细胞浸润）的上皮损伤，而GA处理（10和20μM）后所有这些损伤均得到改善。
抗生素通过HuR诱导肠上皮损伤，GA可通过恢复HuR水平对AIJ发挥保护作用。
