Fig. 1

Experimental design and PFF size distribution. A Male Fischer 344 rats (3-months of age) received two intrastriatal injections of sonicated mouse alpha-synuclein preformed fibrils (α-syn PFFs) or phosphate buffered saline (PBS). Rats were fed Pexidartinib (PLX3397B) or control chow ad libitum starting on the day of surgery until euthanasia at 2- or 6-months post-surgery. Brains were collected for postmortem endpoints including quantification of a-syn phosphorylated at serine 129 immunoreactive (pSynir) neurons, major histocompatibility complex II immunoreactive (MHC-IIir) cells, tyrosine hydroxylase immunoreactive (THir) neurons, and ionized calcium-binding adaptor molecule 1 immunoreactive (Iba1ir) microglia count and size, in the substantia nigra pars compacta (SNpc). B Representative electron micrograph of sonicated α-syn fibrils. C Size distribution of ~ 650 sonicated fibrils prior to injection (mean fibril size-2 months: 35.9 ± 0.06 nm, 6-months: 34 ± 0.57 nm)