title: Comparison of mouse strains and exposure conditions in acute cigarette smoke inhalation studies.
abstract: Cigarette smoke exposures in mice have been conducted under various exposure conditions using different strains as animal models of smoke-related diseases. We exposed cigarette smoke to two strains of mice [C57BL/6J (C57) and AKR/J (AKR)] under two different exposure regimens (1 h or 4 h/day) at equivalent daily exposure amount (concentration × time). After 2 weeks exposure, mice were evaluated using exposure markers and biological responses. Smoke exposure suppressed respiratory parameters dependent on exposure concentration. The 1-h regimen groups generally showed a greater degree of respiratory suppression and relatively lower exposure markers of urinary nicotine metabolites than the corresponding 4-h regimen groups. Tidal volume was more suppressed in AKR compared to C57, while respiratory rate was more suppressed in C57. Plasma exposure markers and respiratory parameters suggested that C57 inhaled more volume of smoke than AKR. Changes in bronchoalveolar lavage fluid (BALF) cytology and enzyme parameters were most noticeable in the 1 h AKR groups. In BALF cytokine concentration, TARC concentration in C57 was higher than AKR, while KC and MCP-1 in AKR were higher than C57. Relative lung/body weight ratio in smoke-exposed C57 was generally higher, as well as the incidence and severity of lesions in respiratory organs compared to AKR. In summary, C57 appeared to inhale relatively more smoke and displayed greater inflammatory changes in respiratory tract than AKR. Comparison of exposure regimens suggests that a longer exposure duration at lower WTPM concentration might deliver a larger dose of smoke than a shorter exposure duration at higher WTPM concentration.
authors.affiliation: Product and Science Division, R & D group, Japan Tobacco Inc., Sumida, Tokyo, Japan. hiroyuki.tsuji@jt.com
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuji
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Daiki
authors.initials: D
authors.lastname: Matsuura
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nishino
authors.forename: K Monica
authors.initials: KM
authors.lastname: Lee
authors.forename: Roger
authors.initials: R
authors.lastname: Renne
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D016207:Cytokines / Q000032:analysis; D005260:Female; D019570:Inhalation Exposure / Q000009:adverse effects* / Q000032:analysis; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D009538:Nicotine / Q000378:metabolism / Q000652:urine; D011014:Pneumonia / Q000209:etiology / Q000276:immunology / Q000473:pathology; D056152:Respiratory Rate / Q000187:drug effects; D012137:Respiratory System / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D013045:Species Specificity; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects* / Q000032:analysis
chemical_list: D015415:Biomarkers; D016207:Cytokines; D014028:Tobacco Smoke Pollution; D009538:Nicotine