title: Rat subchronic inhalation study of smoke from cigarettes containing flue-cured tobacco cured either by direct-fired or heat-exchanger curing processes.
abstract: A subchronic, nose-only inhalation study compared the effects of mainstream smoke from a cigarette containing 100% flue-cured tobacco cured by a direct-fired process to that of a cigarette containing 100% flue-cured tobacco cured by a heat exchanger process. The tobaccos and mainstream smoke from tobaccos cured by the heat exchanger process have been shown to have significantly lower levels of tobacco-specific nitrosamines than tobaccos cured by a direct-fired process. Male and female rats were exposed for 1 h/day, 5 days/wk, for 13 wk to mainstream smoke at 0, 0.06, 0.20, or 0.80 mg wet total particulate matter per liter of air. Clinical signs, body and organ weights, clinical chemistry, hematology, carboxyhemoglobin, serum nicotine, plethysmography, gross pathology, and histopathology were determined. When histologic changes resulting from exposure to smoke from the two types of cigarettes were compared, the only significant difference was increased epithelial hyperplasia of the anterior nasal cavity in males in the high-exposure group for the heat-exchanger cigarette. At the end of the exposure period, subsets of rats from each group were maintained without smoke exposures for an additional 13 wk (recovery period). At the end of the recovery period, there were no statistically significant differences in histopathological findings observed between the heat-exchanger-cured tobacco cigarette when compared to the direct-fired cured tobacco cigarette. The complete toxicological assessment in this study of heat exchanger and direct-fired tobaccos suggests no overall biologically significant differences between the two cigarettes.
authors.affiliation: R. J. Reynolds Tobacco Co., Regulatory Toxicology, Division of Product Stewardship and Toxicology Assessment, PO Box 1487, Winston-Salem, NC 27102, USA. kinsles@rjrt.com
authors.forename: Steven
authors.initials: S
authors.lastname: Kinsler
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Pence
authors.forename: W Keith
authors.initials: WK
authors.lastname: Shreve
authors.forename: Arnold T
authors.initials: AT
authors.lastname: Mosberg
authors.forename: Paul H
authors.initials: PH
authors.lastname: Ayres
authors.forename: John W
authors.initials: JW
authors.lastname: Sagartz
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis; D001835:Body Weight / Q000187:drug effects / Q000208:ethnology; D002248:Carbon Monoxide / Q000032:analysis; D002263:Carboxyhemoglobin / Q000032:analysis; D005260:Female; D019570:Inhalation Exposure / Q000032:analysis; D008297:Male; D009297:Nasal Mucosa / Q000187:drug effects / Q000473:pathology; D009538:Nicotine / Q000097:blood; D009602:Nitrosamines / Q000032:analysis*; D009929:Organ Size; D010991:Plethysmography; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*; D012906:Smoke / Q000032:analysis; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000032:analysis*
chemical_list: D009602:Nitrosamines; D012906:Smoke; D014028:Tobacco Smoke Pollution; D009538:Nicotine; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin