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Occupational asthma can be induced by a number of chemicals at the workplace. Risk assessment of potential sensitizers is mostly performed in animal experiments. With increasing public demand for alternative methods, human precision-cut lung slices (PCLS) have been developed as an ex vivo model. Human PCLS were exposed to increasing concentrations of 20 industrial chemicals including 4 respiratory allergens, 11 contact allergens, and 5 non-sensitizing irritants. Local respiratory irritation was characterized and expressed as 75% (EC25) and 50% (EC50) cell viability with respect to controls. Dose-response curves of all chemicals except for phenol were generated. Local respiratory inflammation was quantified by measuring the production of cytokines and chemokines. TNF-α and IL-1α were increased significantly in human PCLS after exposure to the respiratory sensitizers trimellitic anhydride (TMA) and ammonium hexachloroplatinate (HClPt) at subtoxic concentrations, while contact sensitizers and non-sensitizing irritants failed to induce the release of these cytokines to the same extent. Interestingly, significant increases in T(H)1/T(H)2 cytokines could be detected only after exposure to HClPt at a subtoxic concentration. In conclusion, allergen-induced cytokines were observed but not considered as biomarkers for the differentiation between respiratory and contact sensitizers. Our preliminary results show an ex vivo model which might be used for prediction of chemical-induced toxicity, but is due to its complex three-dimensional structure not applicable for a simple screening of functional and behavior changes of certain cell populations such as dendritic cells and T-cells in response to allergens.

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. 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 smokeinduced 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. 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. Proinflammatory immune responses connected to toxic and subtoxic doses were quantified using ELISA. Additionally, therapeutic intervention with dexamethasone and roflumilast was assessed.

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