Tohoku J. Exp. Med., 2007, 212(2)

Chemopreventive Effect of Selenium-Enriched Japanese Radish Sprout against Breast Cancer Induced by 7,12-Dimethylbenz[a]anthracene in Rats

OSAMU YAMANOSHITA,¹ SHU ICHIHARA,² HIDETOSHI HAMA,³ GAKU ICHIHARA,¹ MOMOKO CHIBA,⁴ MICHIHIRO KAMIJIMA,¹ IWAO TAKEDA⁵ and TAMIE NAKAJIMA¹

¹Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Japan
²National Hospital Organization Nagoya Medical Center, Nagoya, Japan
³Department of Preventive Medicine, Shinshu University School of Medicine, Nagano, Japan
⁴Department of Epidemiology and Environmental Health, Juntendo University School of Medicine, Tokyo, Japan
⁵M I tech Co., Ltd., Nagano, Japan

Breast cancer is one of the major cancers in women, and dietary intake must be controlled to prevent it. Selenium (Se), especially Se compound in vegetables, is thought to be a promising chemopreventive dietary ingredient for preventing breast cancer. In this study, we developed Se-enriched Japanese radish sprout using a special Se-additional fertilizer, and identified the Se chemical forms. The newly developed Se-enriched sprout is produced within a week by the tank forming method, and the major chemical form was identified as Se-methylselenocysteine (MeSeCys) (80%). Then, the chemopreventive effects of the Se-enriched sprout were investigated using Sprague-Dawley female rats with mammary cancer, induced by a single oral dose of 10 mg or 14 mg of 7, 12-dimethylbenz[a]anthracene (DMBA). Mammary tumors were found in 11, 16 and 2 rats treated with DMBA and thereafter fed the basal (n = 34), sprout-added basal (n = 30) and Se-enriched sprout-added test diets (n = 30), respectively. The incidence of mammary tumors was significantly lower in the Se-enriched sprout-added test diet group (7%) than in the basal diet group (32%) or sprout-added basal diet group (53%). In contrast, no significant difference was detected in the numbers and incidence of the tumor between the basal diet group and Se-enriched sprout-added test diet group before DMBA-dosing. These results suggest that the diet supplement of Se-enriched sprout after DMBA-dosing provides a significant chemoprevention against chemical-induced mammary cancer. Thus, Se-enriched sprout may be a useful dietary ingredient for preventing breast cancer.

keywords —— selenium; chemoprevention; 7,12-dimethylbenz[a]anthracene; breast cancer

© 2007 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2007, 212, 191-198

Correspondence: Osamu Yamanoshita, Ph.D., Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.

e-mail: yaman@med.nagoya-u.ac.jp