An immunohistochemical study on manganese superoxide dismutase in Parkinson's disease

We report an immunohistochemical study on manganese superoxide dismutase (Mn SOD) in Parkinson's disease (PD) patients and age-matched control subjects. Overall appearance of immunostaining intensity of nigral neurons did not differ significantly between the PD patients and the control subjects. However, when the immunostaining intensity of each neuron was semiquantitatively analyzed, both very intensely stained (more than normal) neurons as well as neurons stained only weakly were more frequently detected in the lateral part than in the medial and the central parts of the substantia nigra in PD patients. As a result, the proportion of normally stained neurons was significantly smaller in the lateral part of the substantia nigra in PD patients; however, the overall distribution of the neurons among the three rating grades for immunostaining did not differ significantly. The immunostaining intensity of the neuropils in the medial and the central part of the substantia nigra tended to be more intense in PD patients than in the control subjects. Our results suggest up-regulation of Mn SOD mainly in the dendritic processes of the less involved nigral neurons.