Int J Urol. 2003 Mar; 10(3): 160-6.

Preventive effects of urinary bladder tumors induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine in rat by green tea leaves.

Sato D, Matsushima M.

Second Department of Urology, Toho University of Medicine, Tokyo, Japan. sai2uro@oha.toho-u.ac.jp

BACKGROUND: Recently, the anticarcinogenic effects of green tea have been studied in sites other than the urinary tract. Although the incidence of bladder cancer has increased, responses to therapy have been limited. The present work examined the preventive effects of green tea against bladder tumors induced in rats by the carcinogen, N-butyl-N-(4-hydroxybutyl)-nitrosamine(BBN). METHODS: From week 5 to week 9, all the groups were exposed to 0.05% BBN in the drinking water for 5 weeks. Rats were divided into four groups. Group 1 was fed a CE-2 diet and tap water for the entire experimental period and served as the control group. Group 2 was fed the green tea leaves after carcinogen exposure. Groups 3 and 4 received green tea leaves before carcinogen exposure. All rats were killed and examined at 44 weeks. RESULTS: Green tea leaves prevented the growth of BBN-induced urinary bladder tumors when given before the carcinogen. CONCLUSION: Green tea may inhibit tumor initiation in the bladder.