Effect of N-acetyl-L-cysteine on endoplasmic reticulum oxidative stress mediated HepG2 cells apoptosis / 中华传染病杂志

ABSTRACT

Objective To analyze the effect of N-acetyl-L-cysteine(NAC)on endoplasmic reticulum stress mediated HepG2 cells apoptosis and evaluate the role of NAC in the treatment of liver injury.Methods HepG2 cells were treated with thapsigargin(TG)to establish the model of oxidative endoplasmic reticulum stress mediated apoptosis,and NAC was used to intervene in apoptosis.To evaluate the apoptosis,various methods such as MTT assay,flow cytometry,DNA ladder and Western blot were performed.Results After treated with 2 μmol/L TG for 0,24,36 and 48 hours,the vitality of HepG2 cells decreased.The ratio of apoptotic cells increased along with the prolonged treatment duration of TG(0.7%±0.5%,27.6%±6.3%,29.7%±3.3%,47.9%±3.5% respectively,P<0.05),and the production of reactive oxygen species(ROS)also increased in time-dependent manner(14.0%±0.5%,36.1%±3.0%,38.2%±6.0%,48.3%±12.4%,P<0.05).The HepG2 cells showed typical morphologic change of endoplasmic retieulum stress induced by 2 μmol/L TG after 36 h and 48 h.DNA ladder was observed at the same concentration and time point correspondingly.Endoplasmic reticulum stress mediated-apoptosis was confirmed by Western blot.Both 10 mmol/L and 20 mmol/L NAC could protect ceils from apoptosis.The ratio of apoptotic cells decreased to 14.0%±1.3% and 11.0%±0.3%,respectively.The production of ROS decreased to 34.7%±0.8% and 31.5%±2.9%,respectively.The effect was related to the concentration of NAC.Conclusions As a Ca2+-adenosine triphoshatase inhibitor,TG may disrupt intracellular calcium homeostasis,which can induce endoplasmie reticulum stress and apoptosis.NAC,the precursor of the synthesis of-SH,can directly inhibit the ROS reaction and alleviate liver damage,which may play a role in the treatment of liver failure.