Application Progress of in Vitro Cell Exposure Test in Inhalation Toxicology

Inhalation toxicology mainly studies toxic reaction of inhalable substances such as gases, vapors and aerosols to the organism after entering respiratory tract. Currently, in vitro alternative methods are attracting more and more attention due to the advocacy of ethics and welfare for laboratory animals. For in vitro alternatives in inhalation toxicology, the most commonly used method is in vitro cell exposure test, in which model construction and toxicity assessments are critical. Studying toxic effects of inhalable substances on respiratory tract requires simulating the micro-environment where respiratory epithelial cells grow in vivo, then exposing cells to substances. Therefore, inhalation toxicology puts higher demands on cell models and in vitro exposure devices. At present, in vitro cell models have expanded from primary cells, cell lines to co-culture and commercial cell models; a variety of air-liquid interface exposure systems have been developed, exposure time is further extended as well. In this paper, the progress of in vitro cell exposure test applied to inhalation toxicology is reviewed, including the application of in vitro model of respiratory tract, air-liquid interface culture, exposure systems and detection indexs.