Figure 5.

α-Syn inclusion-associated microgliosis and astrogliosis in the SN is not impacted by STN DBS. α-Syn inclusions induced by PFF injection are associated with significantly more MHC-IIir microglia in the SN at the two-month time point compared with rats that received control intrastriatal PBS injections in which inclusions do not form (A, B). STN DBS did not impact the number of MHC-IIir microglia (C). Scale bars: 100 µm. pSyn (red) and GFAP (green) fluorescence intensity were measured in the SNpc of PBS-injected (D) and PFF-injected (E) rats. Mean GFAP intensity in PFF-treated rats is higher (INACTIVE = 597.7 ± 23.7 AU, ACTIVE = 580.0 ± 36.5 AU) than in PBS-treated controls (INACTIVE = 376.7 ± 18.2 AU, ACTIVE = 381.0 ± 25.6 AU, p < 0.0001; F). Scale bars: 50 µm. GFAPir astrocytes from PBS-injected (G) and PFF-injected (H) rat nigras were outlined to produce 2D-rendered paths. Total length of all paths (I) and number of branches (J) were quantified as an indicator of astrocyte complexity. There is a significant positive association between total intensity of GFAP in arbitrary units and total intensity of pSyn (K); ***p ≤ 0.001. Values represent the mean ± SEM.