Figure 5: Reduction of microglial infiltration and GFAP expression after hUCB transplantation (see [25]). Schematic drawings show representative coronal brain sections after hypoxic-ischemic lesion corresponding to Bregma 1.2-( ) 0.2 mm at P21 (a) and P51 (f). Boxes highlight photographed areas (green: CD68 expression in the basal ganglia; red: GFAP expression in the cortex). (b) HI led to an infiltration of CD68 positive microglia. Cells were present at the lesion site throughout the late acute ischemic (P21) and, to a lesser extent, in the chronic postischemic phase ((g) P51). Dotted lines delineate histological defined areas of prominent tissue damage, and these express higher levels of CD68. Long white arrows indicate clusters of CD68 positive cells. Brains of transplanted animals showed a reduced microglial infiltration at both time points compared to nontransplanted animals ((c) P21; (h) P51). In analogy, two weeks following HI a massive upregulation of GFAP encircling the lesion site was observed (d) and maintained until seven weeks of age (i). hUCB transplantation led to a reduced amount of GFAP immunoreactivity around the ischemic zone ((e) P21; (j) P51), thus leaving a larger portion of the remaining cortex spare of the inflammatory reaction ((e) and (j) white dotted line indicates border of cortical areas with lower versus those with higher GFAP expression). Astrocytes in the vicinity of the ischemic zone presented an activated phenotype characterized by a large soma and fewer processes, thus obtaining a more rounded shape ((k) white arrows). In hUCB transplanted animals, a higher number of astrocytes appeared to have a more elongated phenotype with long processes ((l) white arrows). Scale bars: 50  m. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this paper.) This paper is available online at: http://www.sciencedirect.com/science/article/pii/S0006899312011511.