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


CONCLUSIONS
Green tea may inhibit tumor initiation in the bladder.
Sato
Daisuke
D
Second Department of Urology, Toho University of Medicine, Tokyo, Japan. sai2uro@oha.toho-u.ac.jp
Matsushima
Masahiro
M
D000818:Animals; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D002085:Butylhydroxybutylnitrosamine / Q000009:adverse effects*; D028241:Camellia sinensis; D002392:Catechin / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D008517:Phytotherapy; D018515:Plant Leaves; D028321:Plant Preparations / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D013662:Tea; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000517:prevention & control*
D016588:Anticarcinogenic Agents; D028321:Plant Preparations; D013662:Tea; D002085:Butylhydroxybutylnitrosamine; D002392:Catechin