Figure 3.

Triple immunofluorescent detection of TH, α-synuclein and tau, as observed in a control case (A–D) as well as in the SNc and LC from a case diagnosed with PSP (E–L’). Neurons in the SNc from a control case are only immunoreactive for TH (red channel), without any noticeable immunoreactivity for tau and α-synuclein (A and C, respectively). When considering PSP cases at the level of the SNc and besides some neurons single-expressing TH (arrows), neurons containing both LBs and tau aggregates were clearly visible (asterisk). The presence of dystrophic neurites positive for α-synuclein is also often observed (arrowheads). The same holds true at the level of the LC. Panels (I–L) are low-magnification photomicrographs showing (i) TH+ neurons with tau aggregates (arrowheads), (ii) TH+ neurons with LBs (arrows); and (iii) TH+ neurons containing both LBs and tau immunoreactivity (asterisk). It is worth noting the presence of dystrophic neurites immunoreactive for either tau or α-synuclein. Panels (I’,J’) are high-magnification insets taken from (I–L) to better appreciate one TH+ neuron showing tau immunoreactivity and multiple LBs. Scale bar is 50 μm for low-magnification photomicrographs and 12.5 μm for insets.