A histochemical study of iron and ferritin in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced hemiparkinsonian monkeys

Iron is increased in the substantia nigra of patients with Parkinson's disease (PD). The mechanism of its accumulation, however, remains to be explored. In this study, we stereotactically injected MPTP into the unilateral putamen or caudate nucleus of six monkeys. The substantia nigra and the basal ganglia regions were stained for iron and ferritin by histochemical methods. We found a marked increase in the intensity of iron staining in the pars compacta of the substantia nigra. On the other hand, no significant difference was noted between the injected side and the non-injected side in ferritin steining. Such results suggest that the iron accumulation in this model as well as in PD may be a result of nigral degeneration, but unbalanced increase in iron with respect to the amount of ferritin may contribute to the progression of the disease by inducing oxidative stress.