Semi-quantitative analysis of dopaminergic neurons in the substantia nigra. Co-administration of 6-OHDA and DJ-1-binding compound-23 (comp-23) was performed in rats injected with 6-OHDA into the left substantia nigra. After 10 days, treated rats were fixed and brain slices were prepared. (A) Midbrain slices were immunostained by anti-TH antibody. (B) 100% is the number of TH-immunopositive neurons in the contralateral substantia nigra (naive hemisphere). Each value is the mean ± SEM of TH-immunopositive neurons in ipsilateral nigral sections from treated rats (each group, n = 4-6). Significance (Bonferroni/Dunn post hoc comparisons after ANOVA): ***P < 0.001 versus vehicle control rats. †††P < 0.001 vs. 6-OHDA-injected rats.