Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 14, 2016; 22(18): 4484-4500
Published online May 14, 2016. doi: 10.3748/wjg.v22.i18.4484
Role of estrogen receptor β selective agonist in ameliorating portal hypertension in rats with CCl4-induced liver cirrhosis
Cheng-Gang Zhang, Bin Zhang, Wen-Sheng Deng, Ming Duan, Wei Chen, Zhi-Yong Wu
Cheng-Gang Zhang, Bin Zhang, Wen-Sheng Deng, Ming Duan, Wei Chen, Zhi-Yong Wu, Department of Gastrointestinal Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
Cheng-Gang Zhang, Department of General Surgery, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
Author contributions: Zhang CG and Wu ZY designed the research; Zhang CG, Zhang B, Deng WS and Duan M performed the research; Chen W provided vital reagents and analytical tools and revised the manuscript; Zhang CG and Zhang B co-wrote the paper.
Supported by the National Natural Science Foundation for the Youth of China, No. 81400630.
Institutional review board statement: The study was approved by the Research Ethics Committee of Renji Hospital, School of Medicine, Shanghai Jiao Tong University (No. RJ-20151211).
Institutional animal care and use committee statement: All of the animal procedures were conducted in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals (NIH Publications No 80-23, revised in 1996). All experimental animal procedures conformed to the guidelines of the National Institutes of Health Guide for the Care and Use of Laboratory Animals.
Conflict-of-interest statement: No conflict of interest exists whatsoever.
Data sharing statement: The data referred to in this manuscript have been generated solely by the authors. No other party has been involved. Therefore, no additional unpublished data are available.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: Zhi-Yong Wu, MD, PhD, Department of Gastrointestinal Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1630 Dongfang Road, Shanghai 200127, China. zhiyongwu1949@sina.com
Telephone: +86-21-68383732 Fax: +86-21-68383732
Received: December 28, 2015
Peer-review started: December 29, 2015
First decision: January 28, 2016
Revised: February 27, 2016
Accepted: March 18, 2016
Article in press: March 18, 2016
Published online: May 14, 2016
Processing time: 127 Days and 12.9 Hours
Abstract

AIM: To investigate the role of diarylpropionitrile (DPN), a selective agonist of estrogen receptor β (ERβ), in liver cirrhosis with portal hypertension (PHT) and isolated hepatic stellate cells (HSCs).

METHODS: Female Sprague-Dawley rats were ovariectomized (OVX), and liver cirrhosis with PHT was induced by CCl4 injection. DPN and PHTPP, the selective ERβ agonist and antagonist, were used as drug interventions. Liver fibrosis was assessed by hematoxylin and eosin (HE) and Masson’s trichrome staining and by analyzing smooth muscle actin expression. Hemodynamic parameters were determined in vivo using colored microspheres technique. Protein expression and phosphorylation were determined by immunohistochemical staining and Western blot analysis. Messenger RNA levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Collagen gel contraction assay was performed using gel lattices containing HSCs treated with DPN, PHTPP, or Y-27632 prior to ET-1 addition.

RESULTS: Treatment with DPN in vivo greatly lowered portal pressure and improved hemodynamic parameters without affecting mean arterial pressure, which was associated with the attenuation of liver fibrosis and intrahepatic vascular resistance (IHVR). In CCl4-treated rat livers, DPN significantly decreased the expression of RhoA and ROCK II, and even suppressed ROCK II activity. Moreover, DPN remarkedly increased the levels of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS, and promoted the activities of protein kinase G (PKG), which is an NO effector in the liver. Furthermore, DPN reduced the contractility of activated HSCs in the 3-dimensional stress-relaxed collagen lattices, and decreased the ROCK II activity in activated HSCs. Finally, in vivo/in vitro experiments demonstrated that MLC activity was inhibited by DPN.

CONCLUSION: For OVX rats with liver cirrhosis, DPN suppressed liver RhoA/ROCK signal, facilitated NO/PKG pathways, and decreased IHVR, giving rise to reduced portal pressure. Therefore, DPN represents a relevant treatment choice against PHT in cirrhotic patients, especially postmenopausal women.

Keywords: Portal hypertension; Estrogen receptor; Rho-kinase signaling; Nitric oxide; Hepatic stellate cells

Core tip: Liver cirrhosis and portal hypertension (PHT) are subject to gender and estrogen levels. The aim of the present study was to investigate whether estrogen receptor β selective agonists could ameliorate intrahepatic resistance and mitigate PHT in rats with CCl4-induced cirrhosis, and uncover the underlying mechanism by investigating RhoA/ROCK and NO/PKG signaling. The authors propose that treatment with an estrogen receptor β selective agonist could improve cirrhotic PHT via regulating RhoA/ROCK and NO/PKG signaling.