Journal List > J Nutr Health > v.48(5) > 1081408

J Nutr Health. 2015 Oct;48(5):390-397. Korean.
Published online October 30, 2015.  https://doi.org/10.4163/jnh.2015.48.5.390
© 2015 The Korean Nutrition Society
Effects of chronic alcohol and excessive iron intake on mitochondrial DNA damage in the rat liver
Jung-Eun Park, Jeong-Ran Lee and Jayong Chung
Department of Food and Nutrition, Kyung Hee University, Seoul 02447, Korea.

To whom correspondence should be addressed. tel: +82-2-961-0977, Email: jchung@khu.ac.kr
Received August 18, 2015; Revised September 24, 2015; Accepted October 08, 2015.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.

Keywords: alcoholic liver injury; iron; mitochondrial DNA

Figures


Fig. 1
Effects of ethanol and iron on serum ALT and AST activities and liver MDA concentrations. (A) Serum ALT activity, (B) Serum AST activity, (C) Liver MDA concentration. Values are expressed as mean ± SE (n = 6 for each group). Different superscripts show statistical significance (p < 0.05).
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Fig. 2
Liver histology in ethanol and/or iron fed rats (x400). (A) Hematoxylin and eosin (H&E) staining, (B) Perls' Prussian blue staining (iron staining). Arrows show inflammatory cell infiltrations.
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Fig. 3
Effects of ethanol and iron on the integrity of mitochondria DNA (mtDNA) and nuclear DNA. (A) Full-length (15.9 kb) mtDNA PCR products, (B) 16.1 kb nuclear transferrin receptor DNA PCR products. Values are expressed as mean ± S.E (n = 6 for each group). Different superscripts show statistical significance (p < 0.05).
Click for larger image


Fig. 4
Effects of ethanol and iron on the mRNA levels of Cox1 and Nd4 in the rat liver. (A) Gapdh, (B) Cox1, (C) Nd4. Values are expressed as mean ± S.E (n = 6 for each group). Different superscripts show statistical significance (p < 0.05).
Click for larger image

Tables


Table 1
Nucleotide sequence for PCR primers
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Table 2
Body and liver weights, liver iron concentrations, and blood iron parameters after 8-week feeding of ethanol and iron in rats
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Notes

This work was supported by grants from the Basic Science Research Program of the National Research Foundation (NRF-2010-0011226).

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