GTS-21 ameliorated the impaired movement and dopaminergic neuronal cell death in the brains of MPTP-injected mice. (A) The experimental procedure is depicted schematically. Mice were given GTS-21 (2 mg/kg, i.p.) daily for three days prior to MPTP injection. Mice were sacrificed 7 days after MPTP injection for histological and biochemical analyses. (B,C) The rotarod and pole tests were carried out two and six days after the MPTP injection, respectively (n = 8–9 per group). (D,E) TH-positive neuronal cells in the substantia nigra and striatum (representative pictures) (D). The optical density of TH-positive fibers in the striatum and the number of TH-positive cells in the substantia nigra were measured for quantitative analysis (E) (n = 4 per group, 3 sections/brain). (F,G) Protein extracts from the substantia nigra of each group were analyzed using TH, p-CREB, PGC-1, BDNF, and Bcl2 antibodies (n = 4). The figures show representative blots (F) and quantification data (G). The data are presented as the mean ± SEM. * p < 0.05, vs. control group; ** p < 0.01, vs. control group; # p < 0.05 vs. MPTP-treated group; ## p < 0.01 vs. MPTP-treated group.