GPX4 expression in putamen. A. GPX4 immunoreactivity is detectable in cell bodies in the putamen of control brains (white arrowheads). B. Comparison of GPX4 labeling in normal and PD putamen. C. Mean GPX4 volume fraction is higher in PD (n = 12) putamen compared to control putamen (n = 11), although the difference is not significant (P > 0.05). D. Images of TH (Nova Red, red color, marked by black arrows) and GPX4 (DAB-Ni, blue/gray, white arrowheads) in putamen of non-PD (left) and PD (right) brain. Occasional swollen, dystrophic axons are present among the relatively few TH-positive fibers and terminals in PD putamen. Scale bars: 20 μm.