Since ingestion is one of the main routes of entry of nanoparticles (NPs) in our organism, simple and fast in vitro models of the intestinal barrier can be helpful to evaluate NPs risk. The human colon adenocarcinoma Caco-2 cell line has been extensively used due to its ability to differentiate, forming a well-structured cell monolayer. In this study, we have used these differentiated cells as a model of intestinal barrier to evaluate a wide set of effects caused by exposure to silver nanoparticles (AgNPs) with an average size of 7.74 nm. Different parameters such as toxicity, monolayer integrity and permeability (assessed by changes in cells' morphology and gene expression pattern), internalization (uptake), translocation, and induction of DNA damage (DNA breaks and oxidative DNA damage) were evaluated. No significant effects were observed on the monolayer's integrity/permeability after exposure to silver nanoparticles, although cellular uptake was demonstrated by using confocal microscopy. Despite the observed uptake, no translocation of AgNPs to the basolateral chamber was demonstrated with any of the different experimental approaches used. The genotoxic effects evaluated using the comet assay indicate that, although AgNPs were not able to induce direct DNA breaks, its exposure induced a significant increase in the oxidative DNA damage levels, at non-toxic concentrations.

由于摄入是我们生物体内纳米颗粒（NPs）进入的主要途径之一，因此在体外简单快速肠屏障模型可以帮助评估NPs风险。人结肠腺癌Caco-2细胞系由于其分化能力而形成结构良好的细胞单层，因此已被广泛使用。在这项研究中，我们已经使用这些分化的细胞作为肠道屏障模型来评估由暴露于平均大小为7.74 nm的银纳米颗粒（AgNP）引起的多种效应。评估了不同的参数，如毒性，单层完整性和通透性（通过细胞形态和基因表达模式的变化评估），内在化（摄取），易位和DNA损伤的诱导（DNA断裂和氧化性DNA损伤）。暴露于银纳米颗粒后，未观察到对单层完整性/渗透性的显着影响，尽管通过共聚焦显微镜证实了细胞摄取。尽管观察到摄取，但使用的任何不同实验方法均未证明AgNPs移位至基底外侧室。使用彗星试验评估的遗传毒性作用表明，尽管AgNPs不能诱导直接的DNA断裂，但在无毒浓度下，其暴露会导致氧化性DNA损伤水平显着增加。