The impact of e-cigarettes and cigarettes on health has been a hot topic in the field of public health in recent years. In this study, the research team of Sun Yat-sen University compared for the first time the similarities and differences in the effects of cigarettes and e-cigarettes on mouse lung function, inflammatory factors, and protein expression under the same nicotine content, filling a scientific research gap in related fields.
The researchers selected RELX watermelon-flavored e-cigarettes and a commercially available cigarette as samples. Thirty-two mice were randomly divided into four groups and exposed to clean air, low-dose e-cigarette aerosol, high-dose e-cigarette aerosol, and cigarette smoke for 10 weeks, respectively, and multiple indicators were analyzed.
The pathological section results of lung tissue showed that the lung coefficient of mice exposed to cigarettes increased significantly and the tracheal morphology changed, suggesting that there may be lesions in their respiratory system. In contrast, the lung coefficient of mice exposed to e-cigarettes did not change significantly, and the tracheal morphology did not change.
Lung function testing found that cigarette exposure led to significant abnormalities in multiple lung function indicators of mice, but only one indicator in the e-cigarette group decreased. At the same time, pathological results showed that both cigarettes and e-cigarettes may cause abnormalities in the lungs of mice, but the damage caused by cigarettes is more obvious.
Serum inflammatory factor detection and transmission electron microscopy found that both cigarettes and e-cigarettes can cause airway inflammation, but cigarettes are more harmful. Even at twice the nicotine content of cigarettes, e-cigarettes cause less pathological damage to the mouse trachea.
Finally, the researchers also conducted proteomic analysis on the lung tissue of mice. The results showed that the changes in differential proteins caused by cigarettes were more concentrated in inflammation-related pathways, while the abnormal expressions caused by e-cigarettes were fewer and had less impact on inflammatory signaling pathways.
The researchers said that the research results clearly show that exposure to cigarettes and e-cigarettes in large inhalation doses is harmful to the respiratory system. But under the same nicotine dose, the harm of e-cigarette aerosol to the respiratory system is less than that of cigarette smoke.
Because there is no need for combustion, e-cigarettes do not produce tar, and therefore are generally regarded as a harm reduction alternative by the medical community. The Centers for Disease Control and Prevention (CDC) clearly states on its official website that switching from cigarettes or other combustible tobacco products to e-cigarettes may have potential benefits for non-pregnant adult smokers.
However, due to the short time since its introduction, research on e-cigarettes is still insufficient. In recent years, many scientific research institutions and public health organizations have focused on the potential impact of e-cigarettes.
In January 2022, a paper published by researchers from the US Food and Drug Administration (FDA) in "Tobacco Control" pointed out that e-cigarettes are less harmful than cigarettes. After smokers switch to e-cigarettes, the levels of biomarkers of various carcinogens in their urine will decrease, up to 95%.
In September 2022, the "Eighth Independent Report on Nicotine E-cigarette Research" released by the UK Department of Health and Social Care pointed out that compared with cigarettes, the exposure to harmful substances caused by e-cigarettes is significantly reduced, and it can significantly reduce the exposure to biomarkers related to the risk of cancer, respiratory and cardiovascular diseases.
The research team of Sun Yat-sen University said that this study comprehensively and systematically analyzed the relative safety of e-cigarettes at the animal level. It is hoped that more clinical research will be carried out in the future to objectively and deeply evaluate the long-term impact of e-cigarettes.
