title: Dopaminergic cell death precedes iron elevation in MPTP-injected monkeys.
abstract: Though increasing lines of evidence suggest that iron accumulation and iron-induced oxidative stress might be important pathological factors responsible for substantia nigra (SN) cell death in Parkinson's disease (PD), it is still unknown whether iron accumulation is a primary cause or consequence of nigral cell death. Using nuclear microscopy, iron histochemistry, TUNEL method for apoptosis detection, and tyrosine hydroxylase (TH) immunohistochemistry, the present study investigated possible changes in iron contents in the SN and correlations of dopaminergic cell death progression with the process of iron accumulation in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced parkinsonian monkey from 1 d to 18 months after MPTP administration. Our study demonstrated that apoptosis occurred in the ipsilateral SN at 1 d after MPTP injection and the number of TH-positive cells decreased significantly from 1 week onward. However, iron content was significantly increased in the ipsilateral SN from 4.5 months to 18 months after MPTP injection, and the iron increase was significantly correlated to the extent of dopaminergic cell death. These results suggest that dopaminergic cell death induced by MPTP administration might lead to iron accumulation in the monkey SN, and increased iron might contribute to the progression of nigral degeneration.
authors.affiliation: Department of Surgery, National University of Singapore, Singapore, Singapore. yih@bcm.tmc.edu
authors.forename: Yi
authors.initials: Y
authors.lastname: He
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Thong
authors.forename: Timothy
authors.initials: T
authors.lastname: Lee
authors.forename: S K
authors.initials: SK
authors.lastname: Leong
authors.forename: Bo Y
authors.initials: BY
authors.lastname: Mao
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.forename: Frank
authors.initials: F
authors.lastname: Watt
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002467:Cell Nucleus / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D007501:Iron / Q000378:metabolism*; D008252:Macaca fascicularis; D008845:Microinjections; D009410:Nerve Degeneration; D010302:Parkinson Disease, Secondary / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D015259:Dopamine Agents; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D007501:Iron; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine