N-acetyl-serotonin protects HepG2 cells from oxidative stress injury induced by hydrogen peroxide.

Jiying Jiang,Xin Wang,Xiaodong Du,Cuihong Liang,Hailiang Wang,Xianghong Gao,Shuna Yu,Wenbo Yu,Jin Li,Zhengchen Jiang

doi:10.1155/2014/310504

Abstract

Oxidative stress plays an important role in the pathogenesis of liver diseases. N-Acetyl-serotonin (NAS) has been reported to protect against oxidative damage, though the mechanisms by which NAS protects hepatocytes from oxidative stress remain unknown. To determine whether pretreatment with NAS could reduce hydrogen peroxide- (H2O2-) induced oxidative stress in HepG2 cells by inhibiting the mitochondrial apoptosis pathway, we investigated the H2O2-induced oxidative damage to HepG2 cells with or without NAS using MTT, Hoechst 33342, rhodamine 123, Terminal dUTP Nick End Labeling Assay (TUNEL), dihydrodichlorofluorescein (H2DCF), Annexin V and propidium iodide (PI) double staining, immunocytochemistry, and western blot. H2O2 produced dramatic injuries in HepG2 cells, represented by classical morphological changes of apoptosis, increased levels of malondialdehyde (MDA) and intracellular reactive oxygen species (ROS), decreased activity of superoxide dismutase (SOD), and increased activities of caspase-9 and caspase-3, release of cytochrome c (Cyt-C) and apoptosis-inducing factor (AIF) from mitochondria, and loss of membrane potential (ΔΨm). NAS significantly inhibited H2O2-induced changes, indicating that it protected against H2O2-induced oxidative damage by reducing MDA levels and increasing SOD activity and that it protected the HepG2 cells from apoptosis through regulating the mitochondrial apoptosis pathway, involving inhibition of mitochondrial hyperpolarization, release of mitochondrial apoptogenic factors, and caspase activity.

Highlights

It is well established that oxidative stress, characterized by a cellular imbalance in the production and elimination of reactive oxygen species (ROS), plays an important role in the pathogenesis of various liver disorders, including liver inflammation [1,2,3], hepatic cirrhosis [4, 5], hepatoma [6], and hepatic ischemia-reperfusion (I/R) injury [7,8,9]
While NAS alone has no effect on the cell viability of HepG2 cells (Figure 1(c)), we further compared the effect of NAS with another well standardized antioxidant melatonin on cell viability of HepG2 cells and found that there was no difference between H2O2 + NAS group and H2O2 + melatonin group
Hepatic I/R injury occurs in liver transplantation, hepatic resection, abdominal surgery with hepatic vascular occlusion, and coronary bypass surgery [54,55,56,57,58,59], which is a major cause of primary nonfunctioning graft

Summary

Introduction

It is well established that oxidative stress, characterized by a cellular imbalance in the production and elimination of reactive oxygen species (ROS), plays an important role in the pathogenesis of various liver disorders, including liver inflammation [1,2,3], hepatic cirrhosis [4, 5], hepatoma [6], and hepatic ischemia-reperfusion (I/R) injury [7,8,9]. Hydrogen peroxide (H2O2) is an important cause of oxidative injury because its half-life is longer than that of other reactive oxygen species and it can transform into a hydroxyl radical, one of the most destructive free radicals [10]. It is generated from most sources of oxidative stress and can diffuse freely in and out of many kinds of cells and tissues. It is becoming clear that mitochondria play a critical part in cellular bioenergetics

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