The influence of sexual dimorphism on diaphragm muscle after long-term exposure to e-cigarette

Abstract

Smoking is one of the world's major health problems and is the leading risk factor for chronic obstructive pulmonary disease. Electronic cigarettes (e-cigs) have emerged as an alternative to conventional cigarettes. However, just like cigarette smoke, e-cig aerosols contain toxic compounds that can promote inflammation and oxidative stress. This study evaluated exposure to conventional cigarettes and electronic cigarettes and the effects on the diaphragm muscle of mice of both sexes. Male (n = 24) and female (n = 24) C57BL/6 mice were divided into three groups: control group (C), conventional cigarette group (CC), and electronic cigarette group (E-cig). The animals in the CC and E-cig groups were exposed to the respective cigarettes for 60 days, followed by 60 days without exposure at the end of the experiment; blood and diaphragm were collected for analysis. In blood plasma, females from the e-cig group showed elevated levels of creatine kinase and increased levels of IL-6, IL-12, and IL-10. In the diaphragm muscle, exposure to e-cigs increased total protein levels decreased superoxide dismutase activity and altered catalase activity in males and females. In addition, the levels of TNF, IL-6, and IL-12 were higher in both sexes, while females also showed greater levels of IL-10. Our results suggest that even after a period of recovery, e-cig exposure promotes inflammation and diaphragmatic oxidative stress, and females are more susceptible to the effects of e-cig.