Fish oil regulates cell proliferation, protect DNA damages and decrease HER-2/neu and c-Myc protein expression in rat mammary carcinogenesis

Background & aims: The aim of this study is to assess the effect of dietary fish oil (MaxEPA) on DNA-strand breaks, cell proliferation and anti-apoptotic protein expressions in rat mammary carcinogenesis. Methods: Eighty-one female Sprague-Dawley rats were divided into two parts, one for DNA-strand breaks study and the other for immunohistochemical study. Female Sprague-Dawley rats were treated with 7,12-dimethylbenz(alpha)anthracene (DMBA) (0.5 mg/0.2 ml corn oil/100 g body weight) by a tail vein injection. Rats were fed either fish oil or corn oil (0.5 ml/day/rat) by oral gavage. Results: Fish oil-treated group showed significant protection against generation of single-strand breaks (SSBs) (56.1%, P < 0.05) but increased effect (72.3%, P < 0.05) was found in the corn oil-treated group when compared to DMBA control group. Furthermore, fish oil-treated group exhibited substantial decrease in Ki-67 (P < 0.05), HER-2/neu (P < 0.05) and c-Myc (P < 0.05) immunolabelling indices when compared to carcinogen counterpart. However, corn oil treatment resulted in significant increase in the above parameters. Conclusions: The above data support the role of n-3 PUFA as a preventive agent for DNA damages and a potential to inhibit mammary carcinogenesis. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.