Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Jul 1986
Chronic inhalation studies in mice. II. Effects of long-term exposure to 2R1 cigarette smoke on (C57BL/Cum x C3H/AnfCum)F1 mice.
Standardized exposure conditions with Kentucky reference 2R1 cigarettes were used to expose 2,053 (C57BL/Cum x C3H/AnfCum)F1 female mice (nose only) to fresh, whole cigarette smoke. In addition, 1,014 mice were sham-exposed, and 449 mice were held as shelf controls. The protocol entailed exposing mice to smoke (or sham-exposure) on a daily basis, 5 days/week, for 110 weeks and observing remaining mice until death. ⋯ Under these exposure conditions, 2R1 cigarette smoke would seem to have weak carcinogenic activity in mouse lung tissue. Other changes associated with smoke exposure were increased incidence of pigmented alveolar macrophage accumulation, otitis media, and head and neck fibrosarcomas. However, the incidence of nephritis, hematopoietic cancers (e.g., leukemias, lymphosarcomas, and reticulum cell sarcomas), and pulmonary congestion was significantly higher in the sham-exposed animals.