Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Mar 27, 2021; 13(3): 315-327
Published online Mar 27, 2021. doi: 10.4254/wjh.v13.i3.315
Papaya improves non-alcoholic fatty liver disease in obese rats by attenuating oxidative stress, inflammation and lipogenic gene expression
Wanwisa Deenin, Wachirawadee Malakul, Tantip Boonsong, Ittipon Phoungpetchara, Sakara Tunsophon
Wanwisa Deenin, Wachirawadee Malakul, Sakara Tunsophon, Department of Physiology, Faculty of Medical Science, Naresuan University, Muang 65000, Phitsanulok, Thailand
Tantip Boonsong, Department of Biochemistry, Faculty of Medical Science, Naresuan University, Muang 65000, Phitsanulok, Thailand
Ittipon Phoungpetchara, Department of Anatomy, Faculty of Medical Science, Naresuan University, Muang 65000, Phitsanulok, Thailand
Sakara Tunsophon, Centre of Excellence for Innovation in Chemistry, Naresuan University, Muang 65000, Phitsanulok, Thailand
Author contributions: Deenin W performed the experiments, analysed and interpreted the data and wrote the manuscript; Malakul W, Boonsong T and Phoungpetchara I conceptually designed the study, interpreted the data and proofed the manuscript; Tunsophon S designed and supervised the study, interpreted the data, discussed the results and wrote and revised the manuscript; all authors read and approved the final manuscript.
Supported by National Research Council of Thailand, No. R2560B137 (to Tunsophon S) and No. 2562/20 (to Deenin W); and Thailand Research Fund, No. RDG5820017 (to Tunsophon S).
Institutional animal care and use committee statement: The experimental protocol was approved by the institutional animal care and committee of Naresuan University, Phitsanulok, Thailand. No. NU-AE 580714.
Conflict-of-interest statement: All other authors have nothing to disclose.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Sakara Tunsophon, PhD, Assistant Professor, Department of Physiology, Faculty of Medical Science, Naresuan University, 99 Moo 9 TahPoh, Muang 65000, Phitsanulok, Thailand. sakarat@nu.ac.th
Received: October 23, 2020
Peer-review started: October 23, 2020
First decision: November 25, 2020
Revised: December 30, 2020
Accepted: February 11, 2021
Article in press: February 11, 2021
Published online: March 27, 2021
Processing time: 147 Days and 11.3 Hours
Abstract
BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a global health issue that is correlated with obesity and oxidative stress.

AIM

To evaluate the anti-NAFLD effect of papaya in high fat diet induced obesity in rats.

METHODS

Four-week-old male Sprague-Dawley rats were divided into four groups after 1 wk of acclimatization: Group 1 was the rats fed a normal diet (C); group 2 was the rats fed a high fat diet (HFD); group 3 was the rats fed a HFD with 0.5 mL of papaya juice/100 g body weight (HFL), and group 4 was the rats fed a HFD with 1 mL of papaya juice/100 g body weight (HFH) for 12 wk. At the end of the treatment, blood and tissue samples were collected for biochemical analyses and histological assessment.

RESULTS

The results of the HFH group showed significantly reduced body weight (HFH vs HFD, P < 0.01), decreased NAFLD score (HFH vs HFD, P < 0.05), and reduced hepatic total cholesterol (HFL vs HFD, P < 0.01; HFH vs HFD, P < 0.001), hepatic triglyceride (HFH vs HFD, P < 0.05), malondialdehyde (HFL, HFH vs HFD, P < 0.001), tumour necrosis factor-α (HFH vs HFD, P < 0.05) and interleukin-6 (HFH vs HFD, P < 0.05) when compared to the HFD group. However, the liver weight showed no significant difference among the groups. The activities of catalase and superoxide dismutase significantly increased in HFH when compared with the HFD group (P < 0.05 and P < 0.001, respectively). The suppression of transcriptional factors of hepatic lipogenesis, including sterol regulatory element-binding protein 1c and fatty acid synthase, were observed in the papaya treated group (HFH vs HFD, P < 0.05). These beneficial effects of papaya against HFD-induced NAFLD are through lowering hepatic lipid accumulation, suppressing the lipogenic pathway, improving the balance of antioxidant status, and lowering systemic inflammation.

CONCLUSION

These current results provide experimental-based evidence suggesting papaya is an efficacious medicinal fruit for use in the prevention or treatment of NAFLD.

Keywords: High fat diet; Lipogenic gene expression; Non-alcoholic fatty liver disease; Obesity; Oxidative stress; Papaya

Core Tip: High fat diet consumption causes non-alcoholic fatty liver disease (NAFLD). This is one of the major liver diseases found worldwide. Liver fat accumulation leads to dysfunction of liver due to oxidative stress and inflammation. Papaya is an important export fruit from Asian and Latin America. It is a nutrient rich fruit with many medicinal properties. Our present study clearly demonstrated that the hepatoprotective mechanism of papaya against NAFLD was a result of the association of the hypolipidemic, anti-inflammatory, and antioxidant activities. This study provides evidence for the beneficial effects of papaya to reverse the progression of NAFLD in obese rats.