title: Differential protection of pre- versus post-treatment with curcumin, Trolox, and N-acetylcysteine against acrylonitrile-induced cytotoxicity in primary rat astrocytes.
abstract: OBJECTIVE
  This study was designed to examine the differential protection of pre- versus post-treatment with three different antioxidants, curcumin (CUR), Trolox, and N-acetylcysteine (NAC), on acrylonitrile (AN)-induced cytotoxicity in primary rat astrocytes.
  
  
  METHODS
  Primary astrocyte cultures were treated with CUR, Trolox and NAC for 4h prior to, or following 24h treatment with AN (2.5mM). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) release, lipid peroxidation, glutathione, reactive oxygen species (ROS) and mitochondrial membrane potential were measured to evaluate protection associated with the three antioxidants. Knockdown of Nrf2 expression by liposome transfection with siRNA was used to confirm the role of Nrf2 activation in the protection associated with the three antioxidants.
  
  
  RESULTS
  Compared with AN treatment alone, pre-treatment with CUR at either concentration significantly increased cell viability and mitochondrial membrane potential, and reduced glutathione levels; lipid peroxidation and ROS production were significantly decreased as well. NAC also showed significant efficacy in attenuating AN-induced toxicity at higher concentration. However, pre-treatment with Trolox failed to ameliorate the AN-induced toxicity. When post-treatment with Trolox, this antioxidant led to significant protective effects at both concentrations, while CUR and NAC were efficacious only at the higher concentrations. Knockdown of Nrf2 only abolished the protective effects of CUR pre-treatment on AN-induced cytotoxicity, while the protective effects of NAC and Trolox pre-treatment groups showed no differences between the Nrf2-knockdown and non-knockdown treatments.
  
  
  CONCLUSIONS
  The selected antioxidants exert differential cellular protection when administered prior or subsequent to AN-induced cytotoxic events in decreasing cellular viability, antioxidative capacity and mitochondrial function, enhanced cytotoxicity and ROS production. These results suggest that antioxidants should be carefully chosen for their efficacy in preventing or diminishing oxidative damage caused by AN. The differential effect of pre- and post-treatment may be attributed to activation of the Nrf2 signaling pathway.
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Bai
authors.initials: B
authors.lastname: Yu
authors.affiliation: Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Changsheng
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wenjun
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ben
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Hai
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Ma
authors.initials: M
authors.lastname: Jing
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Guangwei
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Shuhua
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
authors.forename: Li
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Aschner
authors.affiliation: Department of Preventive Medicine and Public Health Laboratory Sciences, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Center for Experimental Research, Kunshan Hospital Affiliated to Jiangsu University, Kunshan, Jiangsu 215132, China. Electronic address: lurz@mail.ujs.edu.cn.
authors.forename: Lu
authors.initials: L
authors.lastname: Rongzhu
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage*; D000181:Acrylonitrile / Q000633:toxicity*; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002839:Chromans / Q000008:administration & dosage*; D003474:Curcumin / Q000008:administration & dosage*; D003603:Cytotoxins; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species
chemical_list: D000975:Antioxidants; D002839:Chromans; D003603:Cytotoxins; D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D005978:Glutathione; D003474:Curcumin; D000181:Acrylonitrile; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D000111:Acetylcysteine
keywords: Acrylonitrile; Curcumin; N-Acetylcysteine; Post-treatment; Pre-treatment; Trolox