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Asian Journal of Andrology (2010) 12: 164-170. doi: 10.1038/aja.2009.74; published online 14 December 2009.
High-dose dietary zinc promotes prostate intraepithelial neoplasia in a murine tumor induction model
Young Hwii Ko1, Yu Jeong Woo1, Jin Wook Kim1, Hoon Choi1, Seok Ho Kang1, Jeong Gu Lee1, Je Jong Kim1, Hong Seok Park1 and Jun Cheon1
1 Department of Urology, Korea University School of Medicine, Seoul 136-705, Korea
Correspondence: Dr Hong Seok Park, Department of Urology, Korea University School of Medicine, Seoul 136-705, Korea. Fax: +82-31-412-5194 E-mail: Dr4you@korea.ac.kr
Received 24 July 2009; Revised 31 August 2009; Accepted 30 September 2009; Published online 14 December 2009.
| Abstract |
To evaluate the role of high-dose dietary zinc in the process of prostate malignancy, 60 Sprague-Dawley rats were randomly divided into four groups: tumor induction with carcinogen and hormone (group 1), oral zinc administration without tumor induction (group 2), oral zinc administration with tumor induction (group 3) and a control without zinc administration or tumor induction (group 4). Zinc was supplied orally in the form of zinc sulfate heptahydrate dissolved in drinking water to groups 2 and 3 for 20 weeks. Although the serum level of zinc measured at 20 weeks was maintained similarly in each group (P = 0.082), intraprostatic zinc concentrations were statistically different. Group 1 prostates contained the least amount of zinc in both the dorsolateral and ventral lobes at levels of 36.3 and 4.8 μg g−1, respectively. However, in group 3, zinc levels increased in both lobes to 59.3 and 12.1 μg g−1, respectively, comparable with that of group 4 (54.5 ± 14.6 and 14.1 ± 2.4 μg g−1). In spite of these increases in zinc concentration, the prevalence of prostate intraepithelial neoplasm was rather increased in group 3 (53.3% and 46.7%) compared with group 1 (33.3% and 33.3%) in both dorsolateral and ventral prostate lobes. Although prostate intraepithelial neoplasm did not develop in any prostate in group 4, zinc administration did induce prostate intraepithelial neoplasm in group 2 (46.7% and 40.0%). Thus, although high dietary zinc increased intraprostatic zinc concentrations, it promoted, instead of preventing, prostate intraepithelial neoplasm in a murine prostate malignancy induction model.
Keywords: experimental animal model; prostatic cancer; prostatic intraepithelial neoplasia; zinc |
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