Table 1.
Effects of PEITC-NAC plus MI on lung tumor induction by a mixture of NNK plus BaP in A/J mice (Macroscopic observations)
| Group | No. of mice at beginning of the study | Temporal sequence | Compound (dose, μmol/g diet) | Carcinogen (dose, μmol) | No. of mice at termination | Mean body weight at termination (g ± SD) | Lung tumors |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| % of mice with lung tumors | Tumors/mouse (mean ±
SD) |
|||||||||||||
| Reduction (%) | ||||||||||||||
|
| ||||||||||||||
| Week 27 | Week 44 | 27 Weeks | 44 Weeks | 27 Weeks | 44 Weeks | 27 Weeks | 44 Weeks | 27 Weeks | 44 Weeks | |||||
| 1 | 80 | none | NNK (2) +BaP (2) | 23 (25)b | 22 (55)b | 23.8 ± 2.9 | 24.8 ± 2.2 | 100 | 100 | 19.3 ± 9.1 | 22.5 ± 6.7 | |||
| 2 | 80 | none | NNK (1) +BaP (1) | 25 (25) | 53 (55) | 24.1 ± 3.0 | 26.5 ± 1.8 | 90 | 100 | 4.1 ± 2.4 | 7.4 ± 3.4 | |||
| 3 | 65 | A | PEITC-NAC (15) +MI (56) | NNK (2) +BaP (2) | 17 (25) | 19 (40) | 21.0 ± 1.9 | 22.3 ± 2.1 | 94 | 100 | 4.4 ± 3.0 | 6.2 ± 2.6 | 77** | 72** |
| 4 | 65 | A | PEITC-NAC (15) +MI (56) | NNK (1) +BaP (1) | 18 (25) | 40 (40) | 21.7 ± 2.5 | 23.3 ± 2.6 | 72 | 88 | 1.7 ± 1.4 | 3.0 ± 2.0 | 58* | 59* |
| 5 | 65 | A | PEITC-NAC (9) +MI (56) | NNK (2) +BaP (2) | 19 (25) | 23 (40) | 22.0 ± 2.0 | 22.8 ± 1.6 | 95 | 96 | 5.8 ± 3.2 | 6.9 ± 3.2 | 70** | 69** |
| 6 | 65 | A | PEITC-NAC(9) +MI (56) | NNK (1) +BaP (1) | 19 (25) | 39 (40) | 21.3 ± 2.4 | 23.2 ± 2.4 | 68 | 95 | 1.8 ± 1.5 | 4.0 ± 2.2 | 56* | 46* |
| 7 | 65 | B | PEITC-NAC (15) +MI (56) | NNK (2) +BaP (2) | 18 (25) | 21 (40) | 20.7 ± 1.8 | 22.1 ± 2.8 | 100 | 100 | 8.8 ± 1.5 | 15.2 ± 6.3 | 55** | 32** |
| 8 | 20 | – | PEITC-NAC (15) +MI (56) | none | 10 (10) | 10 (10) | 22.2 ± 2.1 | 24.8 ± 2.2 | 20 | 0 | 0.2 ± 0.4 | 0.2 ± 0.4 | ||
| 9 | 20 | – | PEITC-NAC(9) +MI (56) | none | 10 (10) | 10 (10) | 23.0 ± 1.9 | 25.8 ± 2.0 | 30 | 20 | 0.3 ± 0.5 | 0.2 ± 0.4 | ||
| 10 | 25 | none | none | 10 (10) | 14 (15) | 25.1 | 26.7 ± 2.4 | 10 | 64 | 0.1 ± 0.3 | 0.7 ± 0.6 | |||
Beginning at age 7–8 weeks, groups of female A/J mice were treated by gavage weekly for 8 weeks with a mixture of NNK + BaP (1 or 2 μmol of each) in 0.1 ml cottonseed oil. The mice were maintained on AIN-93G diet from age 5–6 weeks until 1 week after the end of carcinogen treatment, then shifted to AIN-93M diet for the duration of the experiment. Chemopreventive agents were added to the diet according to the temporal sequences shown in the Table. The mice were killed 19 weeks (short-term) or 36 weeks (long-term) after the last carcinogen treatment.
The numbers in parentheses indicate the number of mice scheduled for sacrifice; differences indicate death prior to termination time.
P < 0.05, compared to group 2.
P < 0.05, compared to group 1.