Effect of alcohol on the expression of proinflammatory cytokine genes in primary bronchial epithelial cells in the presence and absence of cigarette smoke extract

Alcohol is a widely consumed psychoactive substance with addictive potential that imposes not only economic and social burdens but also substantial adverse effects on human health. While its actions on the central nervous and gastrointestinal systems are relatively well characterized, its impact on the airways and lungs remains insufficiently defined. This study aimed to determine how alcohol exposure, in the presence or absence of cigarette smoke extract (CSE), influences the expression of pro-inflammatory cytokine genes (IL6, IL8, TNFα) in human bronchial epithelial cells. We employed the BEAS-2B cell line and primary bronchial epithelial cells (PBECs). Cells were treated with ethanol alone (1 or 5 mM), CSE alone (2.5% or 5%), or their combinations (ethanol + CSE) for 12 or 24 hours. In BEAS-2B cells, cellular toxicity and viability were assessed by MTT following exposure to ethanol (0.1–100 mM), 2.5% or 5% CSE, and their combinations. mRNA levels of IL6, IL8, and TNFα were quantified by qRT-PCR after total RNA isolation and cDNA synthesis. Cytokine dynamics in primary bronchial epithelium (healthy donors, smokers, and COPD) varied with time and co-exposure conditions. In healthy cells, IL-8 expression showed a modest rise at 12 hours and largely returned to baseline by 24 hours; in smoker-derived and COPD cells, IL-8 remained generally low across 12–24 hours. For IL-6, specific and reproducible amplification could not be obtained by qPCR in any group, precluding comparative analysis. TNF-α exhibited only limited fluctuations in healthy cells without a clear increase toward 24 hours, whereas expression was mostly suppressed in smoker-derived and COPD epithelium. Under co-exposure, 2.5% CSE combined with 1 mM ethanol markedly elevated IL-8 at 24 hours, while the same CSE level with 5 mM ethanol produced only a modest increase. For IL-6 and TNF-α, a late-phase increase was evident with 1 mM ethanol, whereas 5 mM ethanol tended to suppress expression. Collectively, these findings indicate that alcohol and cigarette smoke jointly recalibrate the proinflammatory response in airway epithelium in a dose- and time-dependent manner: moderate exposure favors heightened inflammation, while higher ethanol doses promote suppression. To strengthen clinical interpretation, future work should include protein-level validation and assessments of epithelial barrier function.