Open Access Research article

Hyperammonia induces specific liver injury through an intrinsic Ca2+-independent apoptosis pathway

Jingjing Li13, Zujiang Yu2, Qiongye Wang1, Duolu Li3, Bin Jia1, Yubing Zhou3, Yanwei Ye4, Shen Shen2, Yanfang Wang3, Shasha Li2, Lu Bai2 and Quancheng Kan13*

Author Affiliations

1 Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China

2 Department of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China

3 Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China

4 Department of Gastrointestinal Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China

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BMC Gastroenterology 2014, 14:151  doi:10.1186/1471-230X-14-151

Published: 22 August 2014

Abstract

Background

Numerous pathological processes that affect liver function in patients with liver failure have been identified. Among them, hyperammonia is one of the most common phenomena.The purpose of this study was to determine whether hyperammonia could induced specific liver injury.

Methods

Hyperammonemic cells were established using NH4Cl. The cells were assessed by MTT, ELISA, and flow cytometric analyses. The expression levels of selected genes and proteins were confirmed by quantitative RT-PCR and western blot analyses.

Results

The effects of 20 mM NH4Cl pretreatment on the cell proliferation and apoptosis of primary hepatocytes and other cells were performed by MTT assays and flow cytometric analyses. Significant increasing in cytotoxicity and apoptosis were only observed in hepatocytes. The cell damage was reduced after adding BAPTA-AM but unchanged after adding EGTA. The expression levels of caspase-3, cytochrome C, calmodulin, and inducible nitric oxide synthase were increased and that of bcl-2 was reduced. The Na+-K+-ATPase activities in hyperammonia liver cells was no signiaficant difference compaired with the control group, but was decreased in astrocytes. NH4Cl pretreatment of primary hepatocytes promoted the activation of mitochondrial permeability transition pores and the mitochondria swelled irregularly.

Conclusions

Hyperammonia induces specific liver injury through an intrinsic Ca2+-independent apoptosis pathway.

Keywords:
Liver injure; Hyperammonia; Calcium overload; Mitochondrial damage