Investigation of gene expression profile of cells after e-cigarette and cigarette smoke exposure
To evaluate the cellular damage caused by e-cigarettes (e-cigs) and combustible cigarettes with respect to inflammatory expression, comparative analysis between two types of e-cigs and three types of combustible cigarettes were conducted. The aerosol of all investigated products was exposed to A549 cell lines. In parallel, the damages of A549 cell lines exposed to the aerosol collected under three different smoking/vaping regimes (ISO, Canadian Intense and CORESTA Recommended Method [CRM] No. 81) were investigated as well. The cytokine and chemokine gene expressions of IL-6, IL-8, IL-12, IL-1β, TNF-α, ICAM-1, MCP-1 and IFN-γ were determined by reverse transcription quantitative PCR (RT-qPCR). The results showed that the exposure to the aerosol of the two types of e-cig samples induced inflammatory gene expression in A549 cell lines. With respect to the induced inflammatory factor expression level, the aerosol collected under different smoking regimes caused different responses: CORESTA > Canada intense > ISO. After the exposure to the aerosol collected under the three regimes, the IFN-γ gene was significantly expressed, which indicates that it is a sensitive biomarker to tobacco smoke. On the contrary, the expression of MCP-1 and IL-8 did not change significantly, which suggests that they did not interfere with the mechanism of inflammatory gene expression induced by tobacco smoke. Under the three regimes, the inflammatory gene expression levels induced by the aerosol of e-cigs were all lower when compared to combustible cigarettes.