Braakhuis Hedwig M, He Ruiwen, Vandebriel Rob J, Gremmer Eric R, Zwart Edwin, Vermeulen Jolanda P, Fokkens Paul, Boere John, Gosens Ilse, Cassee Flemming R
National Institute for Public Health and the Environment (RIVM);
National Institute for Public Health and the Environment (RIVM); Institute for Risk Assessment Sciences (IRAS).
J Vis Exp. 2020 May 13(159). doi: 10.3791/61210.
For toxicity testing of airborne particles, air-liquid interface (ALI) exposure systems have been developed for in vitro tests in order to mimic realistic exposure conditions. This puts specific demands on the cell culture models. Many cell types are negatively affected by exposure to air (e.g., drying out) and only remain viable for a few days. This limits the exposure conditions that can be used in these models: usually relatively high concentrations are applied as a cloud (i.e., droplets containing particles, which settle down rapidly) within a short period of time. Such experimental conditions do not reflect realistic long-term exposure to low concentrations of particles. To overcome these limitations the use of a human bronchial epithelial cell line, Calu-3 was investigated. These cells can be cultured at ALI conditions for several weeks while retaining a healthy morphology and a stable monolayer with tight junctions. In addition, this bronchial model is suitable for testing the effects of repeated exposures to low, realistic concentrations of airborne particles using an ALI exposure system. This system uses a continuous airflow in contrast to other ALI exposure systems that use a single nebulization producing a cloud. Therefore, the continuous flow system is suitable for repeated and prolonged exposure to airborne particles while continuously monitoring the particle characteristics, exposure concentration, and delivered dose. Taken together, this bronchial model, in combination with the continuous flow exposure system, is able to mimic realistic, repeated inhalation exposure conditions that can be used for toxicity testing.
对于空气中颗粒物的毒性测试，已开发出气液界面（ALI）暴露系统用于体外测试，以模拟实际暴露条件。这对细胞培养模型提出了特定要求。许多细胞类型会因暴露于空气中而受到负面影响（例如，干燥），并且仅能存活几天。这限制了这些模型中可使用的暴露条件：通常在短时间内以云雾状（即含有颗粒物的液滴，其会迅速沉降）施加相对较高的浓度。这样的实验条件并不能反映实际长期暴露于低浓度颗粒物的情况。为了克服这些限制，对人支气管上皮细胞系Calu-3的使用进行了研究。这些细胞可以在ALI条件下培养数周，同时保持健康的形态和具有紧密连接的稳定单层。此外，该支气管模型适用于使用ALI暴露系统测试反复暴露于低浓度、实际浓度的空气中颗粒物的影响。与其他使用单次雾化产生云雾的ALI暴露系统不同，该系统使用连续气流。因此，连续流动系统适用于对空气中颗粒物进行反复和长时间的暴露，同时持续监测颗粒物特征、暴露浓度和输送剂量。综上所述，该支气管模型与连续流动暴露系统相结合，能够模拟可用于毒性测试的实际反复吸入暴露条件。
