Acute cigarette smoke exposure induces cytotoxicity and inflammation in living tissue of precision-cut lung slices

Introduction: Chronic obstructive pulmonary disease (COPD) is a severe lung disease with high mortality and increasing prevalence. It is characterized by profound damage of lung parenchyma due to cigarette smoke-induced stress. To understand the underlying mechanisms the need emerged to develop human relevant models. Lipopolysaccharide (LPS) is a widely used model compound which does not directly induce oxidative stress due to lacking radicals. It therefore can not reflect cigarette smoke-induced toxicity in the lung. The aim of this study is to establish precision-cut lung slices (PCLS) as a relevant toxicity model by using cigarette smoke and cigarette smoke condensate in comparison to LPS as model compounds. Methods: Murine PCLS were prepared and exposed submerged to LPS and cigarette smoke condensate, and to cigarette mainstream smoke using the P.R.I.T.® air-liquid interface (ALI) culturing and exposure system. Induced toxicity was assessed by LIVE/DEAD® vitality staining and determination of metabolic activity using the WST-1 assay. Pro-inflammatory immune responses connected to toxic and subtoxic doses were quantified using ELISA. Additionally, therapeutic intervention with dexamethasone and roflumilast was assessed. Results: Concentration dependent toxicity could be shown for both cigarette smoke condensate and cigarette smoke with EC50 of 158 µg/mL and 0.255 µg/cm respectively. This is less compared to data published for A549 with ED50 ranging from 0.330 to 1.78 µg/cm3. Subtoxic and toxic doses of cigarette condensate induced a significant release of tumor necrosis factor (TNF)-a and interleukin (IL)-1a. Release of TNF-a and IL-1a was significantly inhibited by dexamethasone and roflumilast. Conclusion: PCLS represent a promising model to reflect the toxic aspects of cigarette smoke-induced tissue damage occurring in COPD. It furthermore can be used to study pharmacological intervention.