Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 14, 2016; 22(46): 10180-10188
Published online Dec 14, 2016. doi: 10.3748/wjg.v22.i46.10180
Hepatoprotective and antioxidant effects of lycopene on non-alcoholic fatty liver disease in rat
Wei Jiang, Mei-Hua Guo, Xin Hai
Wei Jiang, Mei-Hua Guo, Xin Hai, Pharmacy Department, First Affiliated Hospital of Harbin Medical University, Harbin 150001, Heilongjiang Province, China
Author contributions: Hai X guaranteed the entire study; Jiang W carried out the whole experiment; Guo MH participated in the design of the study, performed the statistical analysis, and drafted the manuscript; Guo MH and Hai X edited and reviewed the manuscript; all authors read and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved by Harbin Medical University Institutional Review Board, Harbin, China.
Institutional animal care and use committee statement: All procedures involving rats in this manuscript were reviewed and approved by the Institutional Animal Care and Use Committee on the Ethics of Animal Experiments of Harbin Medical University (HMU, Protocol Number: 20150301).
Conflict-of-interest statement: We have no financial relationships to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Xin Hai, PhD, Pharmacy Department, First Affiliated Hospital of Harbin Medical University, Harbin 150001, Heilongjiang Province, China. hai_xin@163.com
Telephone: +86-451-85556228 Fax: +86-451-85556228
Received: June 8, 2016
Peer-review started: June 13, 2016
First decision: July 29, 2016
Revised: August 15, 2016
Accepted: October 10, 2016
Article in press: October 10, 2016
Published online: December 14, 2016
Processing time: 187 Days and 2.3 Hours
Abstract
AIM

To evaluate the hepatoprotective effect of lycopene (Ly) on non-alcoholic fatty liver disease (NAFLD) in rat.

METHODS

A rat model of NAFLD was first established by feeding a high-fat diet for 14 wk. Sixty-five rats were randomly divided into normal group, model group and Ly treatment groups. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides (TG), total cholesterol (TC) in serum and low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), free fatty acid (FFA), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) in liver tissue were evaluated, respectively. While the hepatoprotective effect was also confirmed by histopathological analysis, the expression levels of TNF-α and cytochrome P450 (CYP) 2E1 in rat liver were determined by immunohistochemistry analysis.

RESULTS

A significant decrease was observed in the levels of serum AST (2.07-fold), ALT (2.95-fold), and the blood lipid TG (2.34-fold) and TC (1.66-fold) in the dose of 20 mg/kg Ly-treated rats (P < 0.01), compared to the model group. Pretreatment with 5, 10 and 20 mg/kg of Ly significantly raised the levels of antioxidant enzyme SOD in a dose-dependent manner, to 90.95 ± 9.56, 109.52 ± 11.34 and 121.25 ± 10.68 (P < 0.05, P < 0.01), as compared with the model group. Similarly, the levels of GSH were significantly increased (P < 0.05, P < 0.01) after the Ly treatment. Meanwhile, pretreatment with 5, 10 and 20 mg/kg of Ly significantly reduced MDA amount by 30.87, 45.51 and 54.49% in the liver homogenates, respectively (P < 0.01). The Ly treatment group showed significantly decreased levels of lipid products LDL-C (P < 0.05, P < 0.01), improved HDL-C level and significantly decreased content of FFA, compared to the model group (P < 0.05, P < 0.01). Furthermore, the Ly-treated group also exhibited a down-regulated TNF-α and CYP2E1 expression, decreased infiltration of liver fats and reversed histopathological changes, all in a dose-dependent manner (P < 0.05, P < 0.01).

CONCLUSION

This study suggests that Ly has a protective effect on NAFLD, down-regulates expression of TNF-α, and that CYP2E1 may be one of the action mechanisms for Ly.

Keywords: Lycopene; Antioxidant; Hepatoprotective; Non-alcoholic fatty liver; Cytochrome P450 2E1

Core tip: Lycopene (Ly), a phytochemical belonging to the carotenoid family, is a red-colored pigment, apolar and acyclic carotenoid. The present study was designed to evaluate the possible hepatoprotective effect of Ly on non-alcoholic fatty liver disease (NAFLD) in rat. This study represents the first examination of the effects of Ly on the therapy of NAFLD, and showed down-regulated expression of TNF-α and indicated that CYP2E1 may be one of the action mechanisms for Ly.