δ- and γ-tocopherols, but not α-tocopherol, inhibit colon carcinogenesis in azoxymethane-treated F344 rats

in Sciences Citation Index(SCI), 科學引文索引資料庫(SCI)
標題δ- and γ-tocopherols, but not α-tocopherol, inhibit colon carcinogenesis in azoxymethane-treated F344 rats
出版類型SCI(Sciences Citation Index)
出版年度2012
AuthorsFei Guan, 關菲, Guangxun Li 李光勳, Anna Ba Liu 劉八, Mao-Jung Lee 李茂榮, Zhihong Yang 楊志宏, Yu-Kuo Chen 陳與國, Yong Lin 林永, Weichung Joe Shih 施為中, & Chung S. Yang 楊中樞
開始頁644
頁數10
出版日期2012 / 4
其他編號0000
中文摘要

The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention. Herein, we compared the activities of δ-tocopherol (δ-T), γ-T, and α-T in a colon carcinogenesis model. Male F344 rats, seven weeks old, were given two weekly subcutaneous injections of azoxymethane (AOM) each at a dose of 15 mg/kg body weight. Starting 1 week before the AOM injection, the animals were maintained on a modified AIN76A diet, or the same diet containing 0.2% of δ-T, γ-T, α-T, or a γ-T-rich mixture of tocopherols (γ-TmT), until the termination of the experiment at 8 weeks after the second AOM injection. δ-T treatment showed the strongest inhibitory effect, decreasing the numbers of aberrant crypt foci by 62%. γ-T and γ-TmT were also effective, but α-T was not. Immunohistochemical analysis showed that δ-T and γ-T treatments reduced the levels of 4-hydroxynonenal and nitrotyrosine and the expression of cyclin D1 in the colon, preserved the expression of PPAR-γ, and decreased the serum levels of prostaglandin E2 and 8-isoprostane. Supplementation with 0.2% δ-T, γ-T, or α-T increased the respective levels of tocopherols and their side-chain degradation metabolites in the serum and colon tissues. Rather high concentrations of δ-T and γ-T and their metabolites were found in colon tissues. Our study provides the first evidence for the much higher cancer preventive activity of δ-T and γ-T than α-T in a chemically induced colon carcinogenesis model. It further suggests that δ-T is more effective than γ-T.

網址http://cancerpreventionresearch.aacrjournals.org/content/5/4/644.long
期刊名稱Cancer Prevention Research
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