Mass spectrometry-based metabolomics investigation on lung toxicity induced by microplastics exposure from air particulates

Microplastics (< 5 mm in size) are global environmental contaminants that have been ubiquitously detected in a variety of compartments, including water, air and foods. Ingestion and inhalation are considered the major routes of human exposure to microplastics. It was reported that human consumes 74000 to 121000 microplastic particles annually1, among which inhalation was found to contribute approximately one-half of annual exposures. In recent years, emerging evidences have demonstrated that various biological responses, such as inflammation, genotoxicity and apoptosis, were associated with the uptake of microplastics via ingestion. However, little attention has been paid to the toxicity of inhaled microplastics. In this study, we aim to investigate the processes and mechanism of lung toxicity of airborne microplastics at molecular level. Firstly, the outdoor air samples will be collected in Taiyuan and Guangzhou, two megacities each in North and South China with significantly different economic and industrial structures. The latter city is one of the densely plastic contaminated areas in China. The types, shapes, sizes and adhered toxicants of the sampled airborne microplastics will be characterized and compared. Secondly, in vivo cell and in vitro rat models will be established for the investigation of lung toxicity induced by airborne microplastics exposure. In addition to the laboratory exposure experiments, a real-ambient exposure system will be used for assessment of inhaled microplastics from real exposure in a polluted atmospheric environment. Thirdly, the microplastics will be determined in the biological samples including plasma and lung tissues of the control and exposed rats for correlation study, which may provide direct evidence whether airborne microplastics may enter the lung and circulatory fluids in the exposed animals. Lastly, mass spectrometry-based metabolomics will be applied for investigation of perturbed metabolites and metabolic pathways with the exposure of airborne microplastics. The results of this project are expected to provide information for interpreting the biological effects and toxicological mechanisms induced by airborne microplastics and for evaluating the potential regulatory thresholds of airborne microplastics via inhalation.