Wang Ying, Tong Jing, Chang Bing, Wang Baifang, Zhang Dai, Wang Bingyuan
Department of Gastroenterology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.
Mol Med Rep. 2014 Jun;9(6):2352-6. doi: 10.3892/mmr.2014.2126. Epub 2014 Apr 9.
The present study aimed to investigate the effects of alcohol on intestinal epithelial barrier permeability and expression of the tight junction-associated proteins, zonula occludens-1 (ZO-1) and claudin-1. An alcohol-treated Caco-2 intestinal epithelial cell monolayer in vitro model was used to investigate whether alcohol is able to induce intestinal barrier dysfunction and decrease expression of ZO-1 and claudin-1. MTT assay results revealed unaltered cell viability at alcohol concentrations of <5%. Caco-2 cells in the 5% alcohol-treated groups exhibited a significant time-dependent decrease in transepithelial electrical resistance (TEER) and an increase in fluorescent yellow flux rate compared with the control cells. ZO‑l expression exhibited a progressive decline following 20 min of incubation, reached its minimum levels at 60 min and then showed an increasing trend following 60 min of incubation. In addition, claudin-1 expression exhibited a progressive increase following 60 min of incubation, reached its maximum levels at 60 min and then showed an increasing trend following 60 min of incubation. Alterations in the expression of the ZO-l and claudin-1 proteins revealed trends consistent with changes in the TEER value and the fluorescent yellow transmittance rate in the Caco-2 cells. The results of this study indicate that alcohol is able to increase the intestinal epithelial barrier permeability in a dose- and time-dependent manner. Alcohol induces a change in the expression of the tight junction-associated proteins, ZO-1 and claudin-1, which are two major sites of alcohol action, thus increasing intestinal epithelial barrier permeability.
本研究旨在探讨酒精对肠上皮屏障通透性以及紧密连接相关蛋白闭合蛋白-1（claudin-1）和闭锁小带蛋白1（ZO-1）表达的影响。采用酒精处理的体外Caco-2肠上皮细胞单层模型，研究酒精是否能够诱导肠屏障功能障碍以及降低ZO-1和claudin-1的表达。MTT检测结果显示，酒精浓度<5%时细胞活力未改变。与对照细胞相比，5%酒精处理组的Caco-2细胞跨上皮电阻（TEER）随时间显著下降，荧光黄通量率增加。孵育20分钟后，ZO-1表达呈逐渐下降趋势，60分钟时达到最低水平，随后在孵育60分钟后呈上升趋势。此外，孵育60分钟后，claudin-1表达呈逐渐上升趋势，60分钟时达到最高水平，随后在孵育60分钟后呈上升趋势。ZO-1和claudin-1蛋白表达的变化与Caco-2细胞中TEER值和荧光黄透过率的变化趋势一致。本研究结果表明，酒精能够以剂量和时间依赖性方式增加肠上皮屏障通透性。酒精诱导紧密连接相关蛋白ZO-1和claudin-1表达发生变化，这是酒精作用的两个主要位点，从而增加肠上皮屏障通透性。
