• Journal of Nutrition and Health
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• v.38 no.10
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• pp.807-816
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• 2005

The objective of the study was to observe the effect of n-3 PUFA on cell proliferation and apoptosis by determining mRNA and protein of COX-2 and eicosanoid product and the mRNA and protein of Bu and Bcl-2 related to apoptosis in colon carcinogenesis of 1,2- dimethylhydrazine (DMH)-treated rats. Ninety male Sprague Dawley rats weighing about 170g were divided into 3 groups, control and n-3 PUFA supplemented groups (FO group: 6.2 mmoles n-3 PUFA; 2FO group: 12.4 mmoles n-3 PUFA) and fed experimental diet for 14 weeks. All rats were intramuscularly injected with DMH 15 mg/kg twice a week for 6 weeks to deliver total dose of 180 mg/kg body weight. Compared with the control group, 6.2 mmoles n-3 PUFA significantly reduced the levels of mRNA and protein expression of COX-2 and 2-series eicosanoids ($TXB_{2}$ and $PGE_{2}$) and decreased cell proliferation in colonic mucosa. However, high levels of n-3 PUFA supplementation significantly increased the levels of mRNA and protein expression of COX-2, TXB2 and PGE2. and increased cell proliferation which was similar level to that of control group. Compared with the control group, n-3 PUFA, regardless of the amount, significantly increased apoptotic index in colonic mucosa. Western blot and RT-PCR analyses showed that the levels of mRNA and protein expression of Bax were significantly increased by 6.2 mmoles n-3 PUFA, but decreased by 12.4 mmoles n-3 PUFA. The analyses also showed the levels of mRNA and protein expression of Bcl-2 were significantly reduced by 6.2 mmoles n-3 PUFA, but increased by 12.4 mmoles n-3 PUFA. The ratio of Bcl-2/Bax in mRNA and protein was significantly reduced by 6.2 mmoles n-3 PUFA but increased by 12.4 mmoles n-3 PUFA. Overall, these results indicate that n-3 PUFA could be effective in preventing colon carcinogenesis by reducing cell proliferation with lower level of COX-2 and 2-series eicosanoid, and increasing apoptosis by inducing pro-apoptotic gene, Bax and inhibiting anti-apoptotic gene, Bcl-2 in the colonic mucosa of DMH-treated rats. However, high level of n-3 PUFA supplementation could stimulate colon carcinogenesis by increasing cell proliferation and inhibiting apoptosis. (Korean J Nutrition 38(10): 807$\sim$816,2005)

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.839-845
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• 2009

Colorectal cancer is the third most common malignant neoplasm in the world. Much attention has been focused on reducing colon cancer risk through medical properties of natural compound that could act as anticarcinogens. In this study, we evaluated the antioxidant and antigenotoxic effects of Styela plicata (S. plicata) from in vitro experiments. S. plicata extracts showed antioxidant activity measured by TRAP assay and antigenotoxic effect in $200{\mu}M$ $H_2O_2$ induced DNA damage in human leukocytes. Especially, freeze-dried S. plicata extracted with methanol showed the highest level of TRAP (0.225 mM) and inhibition of DNA damage (66.8%). Additionally we observed the effect of S. plicata on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) and DMH induced DNA damage (by comet assay) in male SD rats. The animals were divided into three groups and fed high-fat and low fiber diet (100 g lard+20 g cellulose/kg diet) without (normal control and DMH control) or with a 3% (w/w) of lyophilized S. plicata powder (DMH+S. plicata). One week after beginning the diets, rats were treated with DMH (30 mg/kg, s.c.) for 6 weeks except for normal control group, which was treated saline instead; dietary treatments were continued for the entire experiment. Nine weeks after DMH injection, administration of S. plicata resulted in reduction of ACF numbers, to 82.7% of the carcinogen control value ($7.67{\pm}2.04$ vs. $1.33{\pm}0.53$: p<0.01). S. plicata supplementation induced antigenotoxic effect on DMH-induced DNA damage in the blood cell (% tail intensity: $6.79{\pm}0.26$ vs. $6.13{\pm}0.22$). These data indicate that S. plicata extract has antigenotoxic and anticarcinogenic effects from in vitro experiments and S. plicata exerts a protective effect on the process of colon carcinogenesis, possibly by suppressing the DMH-induced DNA damage in blood cell and the development of preneoplastic lesions in colon.