Table 1

Dose-dependent inhibition of NNK plus BaP-induced lung tumorigenesis by I3C in A/J mice

GroupTemporal sequenceI3C (dose, μmol/g diet)CarcinogenNo. miceMean body weight at termination (g ± SD)Lung tumors
InitialAt terminationTumor incidence (%)Tumors/mouse (mean ± SD)Reduction in tumor multiplicity (%)P*
1NNK + BaP171723.8 ± 2.210021.1 ± 5.2
2A112NNK + BaP131219.3 ± 2.2852.5 ± 2.488<0.0001
3A71NNK + BaP141420.8 ± 1.6865.2 ± 4.075<0.0001
4A30NNK + BaP151421.2 ± 1.41009.8 ± 5.153<0.0001
5A10NNK + BaP181822.4 ± 2.810010.4 ± 3.751<0.0001
6A1NNK + BaP181722.8 ± 2.210017.9 ± 6.1150.19
7B112NNK + BaP151519.6 ± 2.61005.6 ± 3.574<0.0001
8112None121019.9 ± 2.000
9NoneNone101025.7 ± 2.4200.2 ± 0.4

NOTE: Beginning at age 6 to 7 wk, groups of female A/J mice were gavaged with eight biweekly doses of a mixture of NNK + BaP (2 μmol each) in 0.1 mL cottonseed oil. The mice were maintained on AIN-93G diet from age 5 to 6 wk until 1 wk after the end of carcinogen treatment, then shifted to AIN-93M diet for the duration of the experiment. I3C was added to the diet beginning at 1 d after the fourth treatment with the carcinogens or 1 wk after the last carcinogen treatment. The experiment was terminated 27 wk after the first dose of the carcinogens.

  • *Compared with group 1.

  • The duration of I3C administration was as for mice in groups 2 to 6.