L-carnitine protects neurons from 1-methyl-4-phenylpyridinium-induced neuronal apoptosis in rat forebrain culture.
1-Methyl-4-phenylpyridinium ion (MPP+), an inhibitor of mitochondrial complex I, has been widely used as a neurotoxin because it elicits a severe Parkinson's disease-like syndrome with an elevation of intracellular reactive oxygen species (ROS) and apoptosis. L-carnitine plays an integral role in attenuating the brain injury associated with mitochondrial neurodegenerative disorders. The present study investigates the effects of L-carnitine against the toxicity of MPP+ in rat forebrain primary cultures. Cells in culture were treated for 24 h with 100, 250, 500 and 1000 microM MPP+ alone or co-incubated with L-carnitine. MPP+ produced a dose-related increase in DNA fragmentation as measured by cell death ELISA (enzyme-linked immunosorbent assay), an increase in the number of TUNEL (terminal dUTP nick-end labeling)-positive cells and a reduction in the mitochondrial metabolism of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). No significant effect was observed with the release of lactate dehydrogenase (LDH), indicating that cell death presumably occurred via apoptotic mechanisms. Co-incubation of MPP+ with L-carnitine significantly reduced MPP+-induced apoptosis. Western blot analyses showed that neurotoxic concentrations of MPP+ decreased the ratio of BCL-X(L) to Bax and decreased the protein levels of polysialic acid neural cell adhesion molecules (PSA-NCAM), a neuron specific marker. L-carnitine blocked these effects of MPP+ suggesting its potential therapeutic utility in degenerative disorders such as Parkinson's disease, Alzheimer's disease, ornithine transcarbamylase deficiency and other mitochondrial diseases.
Wang
C
C
Division of Neurotoxicology, HFT-132, National Center for Toxicological Research/U.S. Food and Drug Administration, Jefferson, AR 72079, USA. cheng.wang@fda.hhs.gov
Sadovova
N
N
Ali
H K
HK
Duhart
H M
HM
Fu
X
X
Zou
X
X
Patterson
T A
TA
Binienda
Z K
ZK
Virmani
A
A
Paule
M G
MG
Slikker
W
W
Ali
S F
SF
D015655:1-Methyl-4-phenylpyridinium / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002331:Carnitine / Q000494:pharmacology*; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000473:pathology*; D018696:Neuroprotective Agents; D016548:Prosencephalon / Q000187:drug effects / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012794:Sialic Acids / Q000378:metabolism; D013778:Tetrazolium Salts; D013844:Thiazoles; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis; D051020:bcl-X Protein / Q000096:biosynthesis
D018696:Neuroprotective Agents; D012794:Sialic Acids; D013778:Tetrazolium Salts; D013844:Thiazoles; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C021319:polysialic acid; D007770:L-Lactate Dehydrogenase; C022616:thiazolyl blue; D015655:1-Methyl-4-phenylpyridinium; D002331:Carnitine