Lung histomorphological alterations in rats exposed to cigarette smoke and electronic cigarette vapour

Electronic cigarettes are becoming increasingly common as a form of nicotine usage, known as vaping. Numerous studies have demonstrated that using electronic cigarettes may lead to nicotine dependence and has a potentially harmful impact on health. The present study compared the impact of electronic and conventional cigarettes on lung tissue. The experiment included 30 male Wistar rats. The animals were divided into three groups: Group A was exposed to electronic cigarette liquid vapour; group B to conventional smoke; and group C constituted the control group without exposition to the nicotine. In both experimental groups numerous alterations were observed, including a collapse of parenchyma, hyperhagia, hyperplasia of type II of pneumocytes, collagen deposition and an increased number of macrophages within thickened alveolar septa. Additionally, an initial elastolysis was observed. The elastic fibers were disrupted, sparse, irregular and thickened, whereas the numbers of alpha-SMA positive myofibroblasts and blood vessels were highest in the group exposed to conventional cigarette smoke. In conclusion, the usage of the electronic cigarettes leads to milder pathological alterations compared with traditional cigarette smoking. Nevertheless, the histopathological damage caused by vaping may lead to the development of alterations in the lung tissue which consequently hinder gas exchange.