Urine proteomic analysis of the rat e-cigarette model

Urinary proteomics was used to investigate the potential effects of e-cigarettes on the human body. In this study, a rat e-cigarette model was constructed by smoking for two weeks and urine samples before, during, and after e-cigarette smoking were collected. Urine proteomes before-after smoking of each rat were compared individually, while the control group was set up to rule out differences caused by rat growth and development. After smoking, the differential proteins produced by rats shows strong individual variation. Fetuin-B, a biomarker of COPD, and annexin A2, which is recognized as a multiple tumor marker, were identified as the differential proteins in five out of six smoking rats on day 3. To our surprise, odorant-binding proteins expressed in the olfactory epithelium were also found and were significantly upregulated, which may help explain olfactory adaptation. Pathways enriched by the differential proteins shows the evidence that smoking e-cigarettes affects the immune system, cardiovascular system, respiratory system, etc., which provides clues for further exploration of the mechanism of e-cigarettes on the human body. ### Competing Interest Statement The authors have declared no competing interest.