Table 3. Incidences of lesions of the nose in rats in 105-week inhalation study.
| Non-neoplastic lesion | Sex | 0 ppm (49 M, 50 F) | 31 ppm (50 M, 49 F) | 62.5 ppm (50 M, 50 F) | 125 ppm (50 M, 50 F) |
|---|---|---|---|---|---|
| Inflammation, suppurative | M | 5a (1.6)b | 5 (1.6) | 10 (1.7) | 29** (2.6) |
| F | 6 (2.0) | 4 (1.5) | 15* (1.5) | 34** (2.9) | |
| Atrophy, olfactory EPI | M | 2 (1.5) | 49** (1.5) | 50** (1.8) | 50** (2.3) |
| F | 1 (1.0) | 47** (1.9) | 48** (2.3) | 50** (2.7) | |
| Hyperplasia of the respiratory EPI | M | 5 (1.6) | 34** (1.2) | 35** (1.3) | 47** (1.9) |
| F | 7 (1.4) | 31** (1.2) | 41** (1.4) | 50** (2.4) | |
| Metaplasia, squamous respiratory EPI | M | 0 | 2 (1.0) | 6* (1.8) | 26** (2.1) |
| F | 1 (1.0) | 1 (1.0) | 5 (1.4) | 39** (2.3) |
aNumber of animals with lesions.
bAverage severity grade of lesions in affected animals (in parentheses): 1 = minimal, 2 = mild, 3 = moderate and 4 = marked.
*Significantly different (p ≤ 0.05) from the chamber control group by the Poly-3 test.
**p ≤ 0.01.