Fig. 1

A single unilateral intranigral BSSG administration triggers progressive bilateral α-synuclein aggregates in the SNpc. a Representative micrographs of α-synuclein immunostaining. The scale bar = 50 μm is common for all micrographs. b Graph showing α-synuclein (+) area density of panel a. The values stand for the mean ± S.E.M. calculated from the measurements in three anatomical levels. n = 3 independent rats per each time in the BSSG group. The dashed lines correspond to the mock group (black square; n = 6 independent rats) and UT group (white circle; n = 6 independent rats). Φ,*, significant when BSSG group compared with the control groups. Two-way ANOVA, Bonferroni post-test. p < 0.05. c Amplifications showing α-synuclein aggregation patterns with diffuse (red arrow), and condensed (blue arrow) structures revealed by Nissl counterstaining, d dot-like structures and e Lewy neurites-like structures. The scale bar = 15 μm is common for all micrographs. f, g Double immunofluorescence against α-synuclein (blue) and TH (red) with Thioflavin-T counterstaining (green). Representative orthogonal projections from a 1-μm z-confocal optical section are the top left and bottom right panels. The top right panels are the integrated image, and the bottom left panels are a horizontal optical Z-section. f White arrowheads show α-synuclein aggregation within dopaminergic neurons. g Yellow arrowheads indicate colocalization of α-synuclein aggregation with Thioflavin T