Effect of indomethacin on N-(4-(5-nitro-2-firyl)-2-thiazolyl)formamide-induced urinary tract carcinogenesis

The effects of indomethacin on the urinary bladder and renalpelvis in rats treated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide(FANFT) were studied. Two hundred female Sprague-Dawley ratswere divided into four groups. Group 1 received control dietwithout added chemicals. Group 2 was treated with indomethacin(1 mg/kg per day) in the drinking water throughout the experiment.Groups 3 and 4 received 0.2% FANFT in the diet for seven weeksfollowed by control diet. In addition to FANFT, Group 4 receivedindomethacin, 1 mg/kg per day, for the entire experiment. Therats were sacrificed after 92 weeks. There were no urothelialtumors in the control group, one renal pelvic tumor in the indomethacingroup, 4 tumors in the FANFT group and 10 urothelial tumorsin the FANFT ⁺ indomethacin group. The difference between Groups3 and 4 was statistically significant (P < 0.05). Moderateand severe hyperplasia of the renal pelvic and papillary epitheliumwas found in 15 of 48 rats in Group 2 (indomethacin only) ascompared with 6 of 49 control rats (P < 0.05). Moderate andsevere hyperplasia was equally frequent in Groups 3 and 4 (14and 17 animals in each group, respectively). Twenty-four ratsin Group 2 had mammary tumors as compared to 12 animals in Group1 (P < 0.01). Five of the tumors in Group 2 were adenocarcinomas.There was no difference between the number of mammary tumorsin Groups 3 and 4 (36 and 32 animals in each group, respectively).The results suggest that indomethacin enhances FANFT-inducedurinary tract carcinogenesis. Indomethacin also seems to exertsome tumorigenic activity in the mammary gland.