Density (# of cells per mm2) of segmented microglia by brain region-of-interest (ROI) at 3 months post-injection of PBS (top) and PFFs (bottom).
In the PBS-injected control mice, the density of microglia is consistent across ROIs (except the olfactory bulb [MOBgr]), and have low intra-group variability, demonstrating the precision of our approach. Dividing the cell density by the section thickness to obtain an approximate "volumetric density" yields results consistent with the literature (~8,500 cells per mm3; Keller, 2018).
In the PFF-injected mouse brains, the density of cells are increased in most ipsilateral (Ipsi) and contralateral (Contra) ROIs, as expected. The increase in microglial density is higher in regions affected early in this α-synuclein PFF spreading model, such as the ipsilateral piriform and entorhinal cortices.
AIVG = insula (visceral & gustatory cortex); AMG = amygdala; AON = anterior olfactory nucleus; CA1 = CA1 subfield of hippocampus; ENT = entorhinal cortex; MOBgr = main olfactory bulb (granular layer); PIR = piriform cortex; WM-cc = corpus callosum; vSTR = ventral striatum
References
Keller et al., Front. Neuroanat., 12: 83, 2018; doi: 10.3389/fnana.2018.00083
This figure shows the density of segmented microglia in various ipsilateral and contralateral brain regions from mice at 3 months following injection of PBS or PFFs. The number of microglia are highest in regions with anatomical connectivity to the ipsilateral anterior olfactory nucleus.