Influence of smoking on the expression of various cytokines in murine bronchoalveolar lavage fluid cells

Abstract

ABSTRACT The cytokine network plays an important role in the pathogenesis of allergic asthmatic lung. As the influence of smoking on cytokine expression should be considered in delineating the cytokine network, the effects of a single exposure and chronic exposure to smoke on the number and cytokine expression of bronchoalveolar lavage fluid (BALF) cells were evaluated. From a total of 126 BALB/c mice, BALF cells were obtained and analyzed using the quantitative reverse transcription-polymerase chain reaction technique (RT-PCR). The bodyweights of chronic smoking mice were found to be lower when compared to those mice that had not been exposed to smoke. The total number of BALF cells increased after smoking without significant differences in cell classification. Spontaneous mRNA expression of interleukin-1α (IL-1α), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-1β) was detected in all cases. The time courses of their expression patterns after exposure to smoke were similar between the chronic and single smoking mice, except for TGF-β. The levels of IL-1β, IL-1β and TGF-β mRNA increased immediately after the exposure to smoke in chronic smoking mice, whereas the levels of TGF-β mRNA increased 2 h after exposure in the single smoking mice. Moreover, the increase of IL-1α and TGF-1β mRNA in the early phase after exposure was exaggerated in chronic smoking mice. Thus, repeated exposure to smoke may have caused some alterations in the expression mechanism of cytokines such as TGF-β and IL-1α in BALF cells, while it seemed to cause a repeated pattern of acute inflammation after each exposure. In the evaluation of cytokine expression in BALF cells in smokers with various lung diseases, it is recommended that before taking samples a sufficient time interval after the last exposure to smoke be allowed to avoid the effect of acute inflammation caused by smoking.