title: L-ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1.
abstract: Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of l-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measured using the fluorochrome 2',7'-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity.
authors.affiliation: Department of Nursing, Hsin Sheng College of Medical Care and Management, Taoyuan, Taiwan.
authors.forename: Ya-Ni
authors.initials: YN
authors.lastname: Huang
authors.forename: Jiz-Yuh
authors.initials: JY
authors.lastname: Wang
authors.forename: Ching-Tien
authors.initials: CT
authors.lastname: Lee
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Lai
authors.forename: Jia-Yi
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D018920:Coculture Techniques; D004347:Drug Interactions; D004790:Enzyme Induction / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D008694:Methamphetamine / Q000633:toxicity*; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D012313:RNA / Q000737:chemistry / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D008694:Methamphetamine; D012313:RNA; D051547:Heme Oxygenase-1; D048051:p38 Mitogen-Activated Protein Kinases; D001205:Ascorbic Acid