Regular exercise reduces colon tumorigenesis associated with suppression of iNOS

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• 作者：Wataru Aoi ; Yuji Naito ; Tomohisa Takagi ; Satoshi Kokura ; Katsura Mizushima ; Yoshikazu Takanami ; Yukari Kawai ; Yuko Tanimura ; Liu Po Hung ; Ryota Koyama ; Hiroshi Ichikawa ; Toshikazu Yoshikawa
• 关键词：Tumorigenesis ; Azoxymethan ; iNOS ; Anti-inflammation ; Running exercise
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2010
• 出版时间：13 August 2010
• 年：2010
• 卷：399
• 期：1
• 页码：14-19
• 全文大小：314 K

文摘

Several epidemiological studies have shown that regular exercise can prevent the onset of colon cancer, although the mechanism involved is unclear. Expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) is often elevated in an initial step of tumorigenesis and promotes colorectal cancer. We investigated the effect of exercise on colon tumorigenesis associated with iNOS and COX-2 in azoxymethan (AOM)-injected mice. Balb/c mice (8 weeks old) were divided into three groups of 20 animals each, consisting of a sedentary control group, an AOM group, and an exercise plus AOM group. Mice in the groups receiving AOM were injected intraperitoneally with AOM weekly for 2 weeks. Six weeks of regular exercise suppressed the generation of aberrant crypt foci (ACF) in the colon by AOM. Expression of iNOS was decreased by exercise compared with that in sedentary mice along with lower nitrotyrosine level while COX-2 was not changed by either AOM or exercise. Additionally, tumor necrosis factor α (TNFα) was decreased by exercise in the colon and plasma. There was no effect of exercise on the expression of antioxidant enzymes and chaperon protein in the colon. Our results suggest that regular exercise prevents colon tumorigenesis, at least partly via the suppression of iNOS expression associated with anti-inflammation.