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! I I I I I I I I I I I I I I I I I #72 AUTHOR: Leuchtenberger, Cecile and Rudolf Leuchtenberger DATE: 1974 TITLE: DIFFERENTIAL RESPONS OF SNELL'S AND C57 BLACK MICE TO CHRONIC INHALATION OF CIGARETTE SMOKE _CITATION; ONCOLOGY 29:122-138 (1974) ~: Study was designed to examine endogenous factors of the host, such as genetic predisposition to cancer or immunological status, in carcinogensis. Snell's and C57 black mice 3 to 4 months old ( bred in the authors labs) were used in the study. Mice were exposed to chronic inhalations of whole fresh smoke or gas vapor phase under standardized conditions from a commercially available grand of cigarette in a smoking machine constructed in their lab. A detailed post mortem and histopathological exam was carried out on each animal, focusing on the respiratory system and heart. Other organs and tissues were examined, particularly for the presence or absence of tumors. Over 1,500 mice of each strain were used for this study. ,FINDINGS/RESULTS= The Shell's strain differed significantly from the C57 Black strain in that Snell's controls had spontaneous lung adenocarcinomas but no vascular alterations, while c57 Black controls had not lung adenocarcinomas but vascular alterations in lung and heart, C57 Black controls had a significantly higher-frequency of peribronchial and peribronchiolar lymphoid cell infiltrations than Shell's controls. After inhalation of whole smoke, and particularly of gas phase alone, Shell's mice had a significant increa~ in tim frequency in lung carcinomas and an earlier occurrence of pulmonary tumors than controls, wl9le C57 Black mice did not develop any lung adenocarcinomas. The frequency of adenocarcinomas in Shell's was more enhanced in male compared to female mice. Bronchogenlc carcinomas were not ob~rved. There as a significant increa~ of va,~ular changes in lung and heart of C57 Black males and females following inhalation of whole cigarette smoke, while there was no or only a very mild increase in lung or heart of Shell's mice. In C57 Black mice the marked augmentation of vascular changes in lung and heart was ob,~rved only after inhalation of whole smoke, and not alter inhalation of gas phase. CONCLUSIONS: The marked differences between types of spontaneous alteration in Snell's and C57 Black control mice are especially noteworthy when considered in connection with different effects evoked by cigarette smoke in these two strains. The difference in response points to the importance which endogenous host factors play in resistance or susceptibility to chronic inhalation of cigarette smoke, as well as provides some information concerning the mode of action of cigarette smoke. The finding that after cigarette smoke inhalations, higher frequencies of lung cancers were observed only in that strain (Snell's) in which controls developed spontaneous lung cancers while higher frequencies of vascular alterations in lung and heart were observed only in that strain (C57 Black) in which controls developed spontaneous vascular alterations, would suggest that smoke did not elicit new lesions but contributed to pulmonary carcinogensis or vascular alterations by an enhancing activity. o o~ ~o