Henry C J, Kouri R E
J Natl Cancer Inst. 1986 Jul;77(1):203-12.
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. A large number of animals was used so that the smoke generation and animal-holding systems could be tested and evaluated and yet provide significant numbers of animals for exposure to cigarette smoke for a major portion of their lifetime. Deposition of smoke particulates was estimated to be about 125-200 micrograms total particulate matter/lung/day. The only lung cancers observed were diagnosed as alveolar adenocarcinomas (AAC). A total of 19 of 978 smoke-exposed mice and 7 of 651 sham-exposed mice were observed with AAC. The difference between the smoke-and sham-exposed groups was not statistically significant at P less than or equal to .05, but the data suggested that the tumors occurred with a shorter latency in the smoke-exposed group (P = .10). The data were analyzed by various methods, including analysis of subsets of the population of animals. A significant increase in the incidence of lung cancer was observed in one subset; however, this difference was not found in the population as a whole or as a result of any other analyses. 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.
采用肯塔基参考2R1香烟的标准化暴露条件，使2053只（C57BL/Cum×C3H/AnfCum）F1雌性小鼠（仅经鼻）暴露于新鲜的全香烟烟雾中。此外，1014只小鼠进行假暴露，449只小鼠作为饲养对照。实验方案包括每周5天、持续110周，每日让小鼠暴露于烟雾（或假暴露）中，并观察剩余小鼠直至死亡。使用大量动物是为了能够测试和评估烟雾产生及动物饲养系统，同时为小鼠一生中大部分时间暴露于香烟烟雾提供足够数量的动物。据估计，烟雾颗粒的沉积量约为125 - 200微克总颗粒物/肺/天。观察到的唯一肺癌被诊断为肺泡腺癌（AAC）。在978只烟雾暴露小鼠中有19只、651只假暴露小鼠中有7只被观察到患有AAC。烟雾暴露组和假暴露组之间的差异在P≤0.05时无统计学意义，但数据表明烟雾暴露组肿瘤发生的潜伏期较短（P = 0.10）。通过多种方法对数据进行分析，包括对动物群体子集的分析。在一个子集中观察到肺癌发病率显著增加；然而，在整个群体中或其他任何分析中均未发现此差异。在这些暴露条件下，2R1香烟烟雾在小鼠肺组织中似乎具有较弱的致癌活性。与烟雾暴露相关的其他变化包括色素性肺泡巨噬细胞积聚、中耳炎以及头颈部纤维肉瘤的发病率增加。然而，假暴露动物的肾炎、造血系统癌症（如白血病、淋巴肉瘤和网状细胞肉瘤）以及肺充血的发病率显著更高。
