Figure 4.

Microglia and macrophages in human SN pars compacta. A-D) Immunohistochemistry for Iba-1 and counterstained with hematoxylin. A) Microglia have a ramified morphology in both young/middle and older adults. No activation of microglia in SN pars compacta with age was observed. B) Iba-1-positive processes of microglia often approached the bodies of NM-containing neurons (NM - intracellular NM), contacting and surrounding them. C) In people of both age groups, the Iba-1-immunoreactive perivascular macrophages (black arrow) localized near blood vessels (asterisk - vessel lumen) were observed. D) Microglia near clusters of eNM (black arrowhead) always had ramified morphology and showed no signs of activation. E-F) Immunohistochemistry for CD68 and counterstained with hematoxylin. E) In the young/middle aged group, CD68-immunostaining were absent in the brain parenchyma. F) In the older group, discrete CD68-immunopositive granules were visualized in the parenchyma (red arrowhead); single CD68- immunopositive ramified cells were detected (red arrow); in both age groups, the CD68-immunoreactive perivascular macrophages (black arrow) localized near blood vessels (asterisk - vessel lumen) were observed. Scale bar: A) 50 μm; B-F) 20 μm.