Effects of fermented rice bran on DEN‐induced oxidative stress in mice:GSTP1,LINE‐1methylation, and telomere length ratio

Abstract

N‐diethylnitrosamine (DEN), a well‐known carcinogen, not only induces excessive reactive oxygen species but also suppresses DNA methylation. This study investigated the effect of fermented rice bran (FRB) treatment on DEN‐induced oxidative stress through DNA methylation and telomere length analysis. To evaluate the potential protective role of FRB in oxidative stress, two different doses of FRB, DEN, and their combination were administered to mice that were preadapted or not to FRB. Glutathione‐S‐transferase P1 (GSTP1) methylation levels significantly decreased at 2 and 24 hr after FRB and DEN co‐administration in mice with and without pre‐adaptation. Moreover, GSTP1 mRNA was upregulated under DEN‐induced oxidative stress. Furthermore, changes in long interspersed nuclear element‐1 methylation were observed from the viewpoint of genomic instability. In addition, FRB preadapted mice displayed a lower telomere length ratio than the non‐adapted mice, suggesting that FRB adaptation offers advantages over the non‐adapted conditions in terms of inflammation suppression. Practical applications DEN induces excessive ROS, which is associated with oxidative stress on DNA and other cellular components, resulting in inflammation. This study shows that FRB may alleviate DEN‐triggered oxidative stress, based on changes in GSTP1, LINE‐1 methylation, and telomere length ratios, thereby, revealing the potential of dietary intervention during inflammation. Furthermore, this study furthers the current understanding of DNA methylation mechanisms underlying the antioxidant and anti‐inflammatory effects of functional food components. These results indicate that dietary inclusion of FRB may help decrease oxidative DNA damage and its associated inflammation at early stages of a disease.

Molecular and genetic aspects of health risks and their association with adverse environmental conditions and diets (systemic review)

“…Data have been accumulated on the impact of flavonoids, such as genistein, quercetin, and epigallocatechin gallate, on biological systems in the human body. They induce Nrf2/ARE nuclear receptors that regulate expression of antioxidant enzymes and phase II detoxification enzymes coded by such genes as GST (P, T, M) SULT, NAT, NQO1, UGT, and GPX [51]. Various studies have proven that dietary polyphenols (epigallocatechin in green tea, turmeric acid in cinnamon, resveratrol in grapes, and curcumin in curcuma) can induce dramatic changes in epigenome of tumor cells and be used for cancer prevention [52].…”