Fig. 7

Effects of IL-1Ra on MCP-1 chemokine, M1/M2 microglia/macrophages infiltration, and polarization in LPS+HI-exposed brains. Total cell percentages of Iba1+ cells in LPS+HI ± IL-1Ra-exposed frontoparietal cortex, white matter, and caudate putamen nuclei of the right hemisphere at 48 h (a). Decreased relative expression of iNOS (IHC staining) in the right frontoparietal neocortex of LPS+HI+IL-1Ra-exposed rats at 48 h compared to LPS+HI (b). Increased Iba1+ cell percentage of Iba1+Arg1+ cells in the frontoparietal WM of the right hemisphere of LPS+HI+IL-1Ra-exposed rats at 48 h (c). IL-1Ra prevented macrophage activation by keeping them in a ramified morphology (arrows), instead of amoeboid (activated) morphology (arrowheads), as shown by CD68 staining (IHC) at 48 h after LPS+HI (d). Change in the CD68+ cell percentage of activated/quiescent macrophages in LPS+HI ± IL-1Ra-exposed brains (e). IL-1Ra prevented IHC staining of iNOS at 48 h after LPS+HI (f). IL-1Ra increased IF staining of Iba1+Arg1+ microglia/macrophages (arrowhead) in the frontoparietal white matter of the right hemisphere at 48 h (g). IL-1Ra decreased relative expression of MCP-1 (IHC staining) in the brain of LPS+HI-exposed rats at 4 h (h). MCP-1 titer (pg/mg) measured by ELISA within the right cerebral hemisphere at 4 and 24 h after LPS+HI (i). Error bars represent means ± SEM, scale bar = 10 μm, four to six animals per conditions, unpaired t test with Welch correction, * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001, **** p ≤ 0.0001. Abbreviations: Iba1 ionized calcium-binding adapter molecule 1, Arg1 arginase 1, iNOS inducible nitric oxide synthase, MCP-1 monocyte chemotactic protein 1, CD68 cluster of differentiation 68, WM white matter