Bio: Dr. Lan Ma-Hock is a trained food chemist (Diploma) and a Eurotox Registered Toxicologist. She obtained her PhD in Toxicology from the University of Potsdam, Germany. In 2002, she began her career at BASF SE in the Department of Experimental Toxicology and Ecology. Since then, she has headed the Laboratory for Inhalation Toxicology and previously led the Laboratory for Analytical Chemistry from 2002 to 2004. Throughout her tenure, she has overseen numerous in vivo inhalation toxicity studies as principal scientist. Her research involvement extends to various national and international projects focused on nanoparticle toxicity, as well as the toxicity of micro- and nanoplastics. Additionally, Dr. Ma-Hock is a member of scientific expert groups in the field of inhalation toxicity and has authored numerous publications in peer-reviewed journals.

Abstract: Micro-/nanoplastic particles have been detected in the atmosphere, raising concerns about inhalation exposure and its effects on the respiratory tract. This study aimed to investigate the toxicity of polystyrene (PS) and polyamide (PA-6) particles following inhalation in rats. Male Wistar rats were exposed to PS nanoparticles (5 and 50 mg/m³), while female rats inhaled PA-6 particles (2, 10, and 50 mg/m³) over 28 days, with recovery periods of 30 and 90 days. Histopathological examinations, bronchoalveolar fluid (BALF) analyses, and RNA sequencing (RNA-Seq) of lung and liver were performed. Results indicated dose-related histological changes and increased BALF parameters, with neutrophil infiltration being prominent. Inhalation exposure to PA-6 led to prolonged lung inflammation, while mild inflammatory effects were seen for PS. The lung burden reached 4 mg/lung and 3.79 mg/lung after exposure to 50 mg/m³ PS and PA-6, respectively. RNA-Seq of the lungs revealed enrichment of pathways related to inflammation, oxidative stress, and lipid metabolism for both PS and PA-6. In the liver, PA-6 affected lipid metabolism and extracellular matrix, while PS impacted signal transduction pathways. This work combines traditional endpoints with RNA-Seq, providing new insights into the adverse outcomes and biological events related to micro-/nanoplastic exposure.

Acknowledgement: This research is partially funded by the EC Horizon 2020-project NanoHarmony [Grant ID 885931] and is part of the ZonMw/Health Holland project MOMENTUM.