Delayed induction of astrogliosis and microgliosis in mice neonatally injected with soluble Δ71-82 αS or fibrillar αS at 8 months post-injection. Tissue sections were stained with GFAP antibody (A-G), which detects astrocytes, and IBA-1 antibody (H-N), which detects microglia. Representative images were taken of the entorhinal cortex, where a high density of αS pathology tends to form due to neonatal injection (see Figures 2, 4, 5 and 10). An 8-month-old control untreated M20 Tg mouse (A, H) and a M20 Tg mouse injected with 25 μg of 21–140 fibrillar (fib) αS at 2 months post-injection (B, I) show basal levels of astrocytes and microglia. There was no significant increase from basal levels in the brains of a nTg mouse with pathology (C, J) relative to a similar nTg mouse without pathology (D, K) at 8 months post-injection of 25 μg of 21–140 fibrillar αS. Robust astrocyte and microglia activation as observed 8 months after injection in M20 Tg mice with brain αS pathology treated with 25 μg of 21–140 fibrillar αS (E, L). In addition, robust astrogliosis was also observed in M20 Tg mice 8 months after injection of 25 μg of Δ71-82 αS with (F, M), or without (G, N) brain αS pathology. Tissue sections were counterstained with hematoxylin. Scale bar = 50 μm.