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Chronic inhalation of cigarette tobacco smoke by rats

Conference ·
OSTI ID:5260762

Specific-pathogen-free rats were exposed by inhalation to cigarette tobacco smoke in a regimen considered to result in a maximal tolerated dose. Total pulmonary deposition of smoke particulates from a single cigarette was 0.25 mg in young rats. Rats were exposed to smoke from 7 cigarettes per day for up to 2.5 years, at which time 30% of the exposed rats remained alive. Mortality of smoke-exposed animals was not different from that of untreated and sham-exposed controls. Nine percent of the exposed animals had tumors in the respiratory tract as opposed to only 1% tumor incidence among the control animals. Smoke exposure did not change the total percent of animals with at least one tumor at some site in the body. However, relative to controls, exposed rats had significantly fewer tumors in the hypophysis, hematopoietic-lymphoid system, uterus, and ovary and an increased number of tumors in the dermis in addition to the respiratory tract. Several non-neoplastic changes were observed throughout the respiratory tract. Hyperplastic and metaplastic areas were seen in the epithelium of the nasal turbinates, larynx, and trachea of exposed animals at death. Lungs of exposed rats contained areas of focal alveolitis.

Research Organization:
Oak Ridge National Lab., TN (USA); National Inst. of Environmental Health Sciences, Research Triangle Park, NC (USA); National Cancer Inst., Bethesda, MD (USA). Div. of Cancer Cause and Prevention
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5260762
Report Number(s):
CONF-791002-7
Country of Publication:
United States
Language:
English