While Taiwan researchers previous studies revealed that lipids played an important role for Zinc oxide (ZnO) particles-induced toxicity in humans and rats, the knowledge of lipid perturbation of ZnO particles on the respiratory system is still limited. The responses of phosphorylcholine-containing lipid (PC-CL) including phosphatidylcholines and sphingomyelins from the lungs of rats inhaled nano- or fine-sized ZnO particles were examined by researchers at National Taiwan University (NTU).
The possible molecular mechanisms and potential lipid biomarkers of ZnO particles in the respiratory system were suggested by Dr. Tsun-Jen Cheng, Dr. Wan-Yu Lin, Dr. Chuan-Ho Tang, and Dr. Ching-Yu Lin’s groups. The results showed that ZnO particles-induced lipid perturbations were associated with anti-oxidation, membrane conformation, and cellular signal transduction in the rat lung. This study has been published as,”LC-MS-based lipidomics to examine acute rat pulmonary responses after nano- and fine-sized ZnO particle inhalation exposure” in Nanotoxicology12(5):439-452.
This study was mainly conducted by Dr. Sheng-Han Lee and as part of Dr. Lee’s doctoral dissertation. Dr. Lee’s mentors included Dr. Ching-Yu Lin, an associate professor in Institute of Environmental Health in the National Taiwan University College of Public Health, Dr. Tsun-Jen Cheng, a professor in the Institute of Occupational Medicine and Industrial Hygiene, Dr. Wan-Yu Lin, an associate professor in the Institute of Epidemiology and Preventive Medicine, and Dr. Chuan-Ho Tang, an associate professor in National Museum of Marine Biology and Aquarium.
This study examined PC-CL responses in the respiratory system of rats by using a liquid chromatography-mass spectrometry (LC-MS)-based lipidomic approach. Male Sprague-Dawley rats were inhaled with a series of doses of nano-sized or fine-sized ZnO particles. After 24 hours, the lung tissues were taken for lipid measurements, followed by multivariate statistical analysis, such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) combined with univariate statistical analysis, such as Mann-Whitney U test with false discovery rate control to draw the plausible molecular pictures and suggest unique lipid signature for ZnO particle exposure.
The results of PCA and PLSDA models showed that the lipid profiles in the fine-sized and the high-concentration nano-sized particle-treated groups were discriminated from other groups. The deceasing trends of lyso-phosphatidylcholines, plasmenylcholines, and sphingomyelins, as well as the increasing trend of diacyl- phosphatidylcholines reflected the perturbation of ZnO particle exposure in the rat respiratory system. These lipid changes were associated with cell anti-oxidation, energy metabolism, DNA damage, and membrane stability to mitigate ZnO particle-induced pulmonary oxidative inflammation. Additionally, PC(18:0/18:1) was selected from the total 102 detected lipids for the possible biomarker of the ZnO particle exposure. Later biomarker evaluation is essential to confirm the researchers findings. The results of this study suggested the plausible molecular mechanisms and potential biomarkers involving in toxicity of ZnO particles.