Table 1.

Weights of urinary bladders with OH-BBN induced lesions in Fischer-344 rats treated with naproxen and NO-naproxen

Treatment*Mean final body weights (g)Urinary bladder + lesions (mg)Number of large urinary bladder cancers
Agent started 2 wk post–OH-BBN
    NO-naproxen, 550 ppm in diet232186 ± 22 (71% ↓)§7/30 (73% ↓)§
    NO-naproxen, 183 ppm in diet231161 ± 11 (75% ↓)§6/30 (77% ↓)§
    Naproxen, 128 ppm in diet225217 ± 32 (66% ↓)§8/30 (69% ↓)§
    None220641 ± 10425/29
Agent started 3 mo post–OH-BBN
    NO-naproxen, 550 ppm in diet227136 ± 7 (58% ↓)§2/29 (86% ↓)§
    Naproxen, 400 ppm in diet226148 ± 15 (54% ↓)§1/30 (94% ↓)§
    None224323 ± 3315/30
  • *Rats received OH-BBN beginning at 56 d of age. Treatment with naproxen and NO-naproxen initiated either 2 wk or 3 mo after the final OH-BBN treatment; studies terminated 8 and 7 mo after final OH-BBN, respectively.

  • Urinary bladder plus lesion weights were those observed at sacrifice of the rats. Values are means ± SEM (number in parenthesis is percent decrease from control).

  • Values represent the number of rats with urinary bladder weights of ≥200 mg divided by the number of rats in the group. Number in parenthesis is percent decrease from control.

  • §Significantly different (P < 0.01) from the respective control group.