title: Lung inflammatory effects, tumorigenesis, and emphysema development in a long-term inhalation study with cigarette mainstream smoke in mice.
abstract: Cigarette smoking is the leading cause of lung cancer and chronic obstructive pulmonary disease, yet there is little mechanistic information available in the literature. To improve this, laboratory models for cigarette mainstream smoke (MS) inhalation-induced chronic disease development are needed. The current study investigated the effects of exposing male A/J mice to MS (6h/day, 5 days/week at 150 and 300 mg total particulate matter per cubic meter) for 2.5, 5, 10, and 18 months in selected combinations with postinhalation periods of 0, 4, 8, and 13 months. Histopathological examination of step-serial sections of the lungs revealed nodular hyperplasia of the alveolar epithelium and bronchioloalveolar adenoma and adenocarcinoma. At 18 months, lung tumors were found to be enhanced concentration dependently (up to threefold beyond sham exposure), irrespective of whether MS inhalation had been performed for the complete study duration or was interrupted after 5 or 10 months and followed by postinhalation periods. Morphometric analysis revealed an increase in the extent of emphysematous changes after 5 months of MS inhalation, which did not significantly change over the following 13 months of study duration, irrespective of whether MS exposure was continued or not. These changes were found to be accompanied by a complex pattern of transient and sustained pulmonary inflammatory changes that may contribute to the observed pathogeneses. Data from this study suggest that the A/J mouse model holds considerable promise as a relevant model for investigating smoking-related emphysema and adenocarcinoma development.
authors.affiliation: Philip Morris Research Laboratories GmbH, 51149 Cologne, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Stinn
authors.forename: Ansgar
authors.initials: A
authors.lastname: Buettner
authors.forename: Horst
authors.initials: H
authors.lastname: Weiler
authors.forename: Baerbel
authors.initials: B
authors.lastname: Friedrichs
authors.forename: Sonja
authors.initials: S
authors.lastname: Luetjen
authors.forename: Frans
authors.initials: F
authors.lastname: van Overveld
authors.forename: Kris
authors.initials: K
authors.lastname: Meurrens
authors.forename: Kris
authors.initials: K
authors.lastname: Janssens
authors.forename: Stephan
authors.initials: S
authors.lastname: Gebel
authors.forename: Regina
authors.initials: R
authors.lastname: Stabbert
authors.forename: Hans-Juergen
authors.initials: HJ
authors.lastname: Haussmann
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D004646:Emphysema / Q000139:chemically induced*; D019570:Inhalation Exposure; D008168:Lung / Q000187:drug effects*; D008297:Male; D051379:Mice; D011014:Pneumonia / Q000139:chemically induced*; D012906:Smoke; D014026:Nicotiana
chemical_list: D012906:Smoke