Activated microglial cells in the substantia nigra compacta (SNc). (A): density of OX6-positive cells in the SNc of female and male rats of different experimental groups treated with vehicle or 6-OHDA. The microglial cells were quantified as the number cells per mm3, and the data are means ± SEM. *p < 0.05 compared with rats treated with vehicle, #p < 0.05 compared with rats treated with 6-OHDA alone (One-way ANOVA and Bonferroni post-hoc test). (B-G): photomicrographs showing activated microglial cells at central levels of the substantia nigra in different experimental groups. Microglial activation was significantly higher in male rats and ovx female rats treated with 6-OHDA alone (D, G). Scale bar: 100 μm.