Effects of chronic alcohol and excessive iron intake on mitochondrial DNA damage in the rat liver / 한국영양학회지

ABSTRACT

PURPOSE: In this study, we investigated the effects of chronic alcohol and excessive iron intake on mitochondrial DNA (mtDNA) damage and the progression of alcoholic liver injury in rats. METHODS: Twenty-four Sprague-Dawley male rats were divided into four groups (Control, EtOH, Fe, and EtOH + Fe), and fed either control or ethanol (36% of total calories) liquid diet with or without 0.6% carbonyl iron for eight weeks. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malondialdehyde concentrations were measured by colorimetric assays. Liver histopathology was examined by Hematoxylin-eosin staining of the fixed liver tissues. The integrity of the hepatic mtDNA and nuclear DNA was measured by long-range PCR. The gene expression levels of cytochrome c oxidase subunit 1 (Cox1) and NADH dehydrogenase subunit 4 (Nd4) were examined by real-time PCR. RESULTS: Serum ALT and AST activities were significantly higher in the EtOH+Fe group, as compared to the Control group. Similarly, among four groups, liver histology showed the most severe lipid accumulation, inflammation, and necrosis in the EtOH + Fe group. PCR amplification of near-full-length (15.9 kb) mtDNA showed more than 50% loss of full-length product in the liver of the EtOH + Fe group, whereas amounts of PCR products of a nuclear DNA were unaffected. In addition, the changes in the mtDNA integrity showed correlation with reductions in the mRNA levels of mitochondrial gene Cox1 and Nd4. CONCLUSION: Our data suggested that the liver injury associated with excessive iron and alcohol intake involved mtDNA damage and corresponding mitochondrial dysfunction.