Role of reactive nitrogen and reactive oxygen species against MPTP neurotoxicity in mice.
There is growing evidence indicating that reactive nitrogen species (RNS) and reactive oxygen species (ROS) are a major contributor to the pathogenesis and progression of Parkinson's disease. Here we investigated whether edaravone (free radical scavenger), minocycline (inducible nitric oxide synthase, iNOS inhibitor), 7-nitroindazole (neuronal NOS, nNOS inhibitor), fluvastatin (endothelial NOS, eNOS activator) and pitavastatin (eNOS activator) can protect against MPTP neurotoxicity in mice under the same condition. The present study showed that 7-nitroindazole could protect dose-dependently against the striatal dopamine depletions in mice 5 days after MPTP treatment. In contrast, edaravone, minocycline, fluvastatin and pitavastatin did not show the neuroprotective effect on MPTP-induced striatal dopamine depletion. Our immunohistochemical study showed that TH (tyrosine hydroxylase) and DAT (dopamine transporter) immunoreactivity was decreased significantly in the striatum and substantia nigra 5 days after MPTP treatment. The administration of 7-nitroindazole showed a protective effect against the severe reductions in levels of TH and DAT immunoreactivity in the striatum and substantia nigra 5 days after MPTP treatment. Furthermore, our Western blot analyses study showed the remarkable loss of TH protein levels in the striatum 5 days after MPTP treatment. In contrast, 7-nitroindazole prevented a significant loss in TH protein levels in the striatum 5 days after MPTP treatment. On the other hand, GFAP (glial fibrillary acidic protein) immunoreactivity increased significantly in the striatum and substantia nigra, 5 days after MPTP treatment. 7-Nitroindazole ameliorated severe increases in number of GFAP immunoreactive astrocytes in the striatum and substantia nigra 5 days after MPTP treatment. Furthermore, our Western blot analyses study showed the increase of GFAP protein levels in the striatum 5 days after MPTP treatment. 7-Nitroindazole prevented a significant increase in the GFAP protein levels in the striatum 5 days after MPTP treatment. The present results indicate that 7-nitroindazole can protect dose-dependently against the striatal dopamine depletions in mice 5 days after MPTP treatment. In contrast, edaravone, minocycline, fluvastatin and pitavastatin did not show the neuroprotective effect on MPTP-induced striatal dopamine depletions. These findings demonstrate that the overexpression of nNOS may play a major role in the neurotoxic processes of MPTP, as compared to the production of ROS, the overexpression of iNOS and the modulation of eNOS. Thus, our findings provide strong evidence for neuroprotective properties of nNOS inhibitor in this animal model of Parkinson's disease.
Yokoyama
Hironori
H
Department of Neurobiology and Therapeutics, Graduate School and Faculty of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan.
Takagi
Sho
S
Watanabe
Yu
Y
Kato
Hiroyuki
H
Araki
Tsutomu
T
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000037:antagonists & inhibitors; D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D019610:Cytoprotection / Q000187:drug effects; D004195:Disease Models, Animal; D004298:Dopamine / Q000172:deficiency / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000187:drug effects / Q000378:metabolism; D005911:Gliosis / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D006719:Homovanillic Acid / Q000378:metabolism; D007191:Indazoles / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018696:Neuroprotective Agents / Q000494:pharmacology; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D050483:Dopamine Plasma Membrane Transport Proteins; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D005904:Glial Fibrillary Acidic Protein; D007191:Indazoles; D018696:Neuroprotective Agents; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D015102:3,4-Dihydroxyphenylacetic Acid; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; D014446:Tyrosine 3-Monooxygenase; C080122:7-nitroindazole; D004298:Dopamine; D006719:Homovanillic Acid