Quantification on Immunostained Tissue Sections

TH immunocytochemistry was used for evaluating the loss of substantia nigra pars compacta dopaminergic cell bodies and that of striatal dopaminergic nerve endings after 6-OHDA lesioning. Counts of TH⁺ cell bodies were performed according to protocols described before (Dos-Santos-Pereira et al., 2016), and results were expressed in TH⁺ neurons/0.5 mm². To evaluate the loss of dopaminergic nerve endings and the intensity of the astrocyte reaction after 6-OHDA lesioning, we measured optical densities (OD) of the TH and GFAP immuno-signals within the dorsal striatum. Results were expressed in % of OD in sham-operated mice. For descriptive purposes, microglial cells were categorized according to morphological criteria previously established, and we measured the number of microglial reactive cells in the dorsal striatum as reported previously (Gomes et al., 2015). Results were expressed in Iba-1+ cells/0.5 mm².