Division of Microbiology, National Center for Toxicological Research, US-Food and Drug Administration, Jefferson, AR 72079, USA.
Int J Mol Sci. 2022 Apr 27;23(9):4851. doi: 10.3390/ijms23094851.
The gastrointestinal tract (GIT) is exposed to xenobiotics, including drugs, through both: local (oral) and systemic routes. Despite the advances in drug discovery and in vitro pre-clinical models, there is a lack of appropriate translational models to distinguish the impact of these routes of exposure. Changes in intestinal permeability has been observed in different gastrointestinal and systemic diseases. This study utilized one such xenobiotic, arsenic, to which more than 200 million people around the globe are exposed via their food, drinking water, work environment, soil, and air. The purpose of this study was to establish an in vitro model to mimic gastrointestinal tract exposure to xenobiotics via oral or intravenous routes. To achieve this, we compared the route (mimicking oral and intravenous exposure to GIT and the dose response (using threshold approach) of trivalent and pentavalent inorganic arsenic species on the permeability of in vitro cultured polarized T84 cells, an example of intestinal epithelial cells. Arsenic treatment to polarized T84 cells via the apical and basolateral compartment of the trans-well system reflected oral or intravenous routes of exposure in vivo, respectively. Sodium arsenite, sodium arsenate, dimethyl arsenic acid sodium salt (DMA), and disodium methyl arsonate hydrate (MMA) were assessed for their effects on intestinal permeability by measuring the change in trans-epithelial electrical resistance (TEER) of T-84 cells. Polarized T-84 cells exposed to 12.8 µM of sodium arsenite from the basolateral side showed a marked reduction in TEER. Cytotoxicity of sodium arsenite, as measured by release of lactate dehydrogenase (LDH), was increased when cells were exposed via the basolateral side. The mRNA expression of genes related to cell junctions in T-84 cells was analyzed after exposure with sodium arsenite for 72 h. Changes in TEER correlated with mRNA expression of focal-adhesion-, tight-junction- and gap-junction-related genes (upregulation of and genes and downregulation of and . Overall, exposure to sodium arsenite from the basolateral side was found to have a differential effect on monolayer permeability and on cell-junction-related genes as compared to apical exposure. Most importantly, this study established a preclinical human-relevant in vitro translational model to assess the changes in permeability and cytotoxicity during exposure, mimicking oral or intravenous routes.
胃肠道（GIT）通过局部（口服）和全身途径接触到包括药物在内的外源性物质。尽管在药物发现和体外临床前模型方面取得了进展，但仍缺乏适当的转化模型来区分这些暴露途径的影响。在不同的胃肠道和全身性疾病中观察到肠道通透性的变化。本研究利用一种外源性物质砷，全世界有超过 2 亿人通过食物、饮用水、工作环境、土壤和空气接触到这种物质。本研究的目的是建立一种体外模型，以模拟胃肠道通过口服或静脉途径接触外源性物质。为此，我们比较了途径（模拟口服和静脉暴露于胃肠道）和剂量反应（使用阈值方法），研究了三价和五价无机砷形态对体外培养的极化 T84 细胞（肠上皮细胞的一个例子）通透性的影响。通过跨膜系统的顶侧和基底外侧隔室对极化 T84 细胞进行砷处理，分别反映了体内的口服或静脉暴露途径。评估了亚砷酸钠、砷酸钠、二甲基砷酸单钠盐（DMA）和二甲基砷酸二甲酯水合物（MMA）对肠道通透性的影响，方法是测量 T-84 细胞跨上皮电阻（TEER）的变化。从基底外侧侧给予 12.8 µM 亚砷酸钠的极化 T-84 细胞，TEER 明显降低。当细胞从基底外侧侧暴露时，亚砷酸钠的细胞毒性（通过乳酸脱氢酶（LDH）释放测量）增加。用亚砷酸钠处理 T-84 细胞 72 小时后，分析了与细胞连接相关的基因的 mRNA 表达。TEER 的变化与细胞连接相关基因（粘着斑基因、紧密连接基因和缝隙连接基因的上调和下调）的 mRNA 表达相关。总的来说，与顶侧暴露相比，从基底外侧侧暴露于亚砷酸钠对单层通透性和细胞连接相关基因有不同的影响。最重要的是，本研究建立了一种临床前的人类相关体外转化模型，用于评估暴露期间通透性和细胞毒性的变化，模拟口服或静脉途径。
