Fig. 5

Delayed microglial activation in the retina 7 weeks after temporal SE. Representative confocal photomicrographs of microglial activation in non-stimulated controls NSC (a) and 7 weeks after SE (b). Arrow heads in (a) and (b) depict Iba1⁺ cells in IPL and GCL. Arrows in B mark Iba1⁺ processes in the ONL. Representative images of different Iba1⁺ cell morphologies, including ramified (RAM), intermediate (INT), and round/amoeboid (R/A) (c). Note the elongated cell soma and thicker proximal processes in INT compared the RAM cells. Quantification of numbers of Iba1⁺ cells in the ipsi- and contralateral retina 7 weeks following SE compared to NSC showed an increase after SE (d). Quantification of the relative percentage of microglia with the three different morphologies revealed a relative reduction in ramified and an increase in amoeboid morphology in the SE group (e). Biochemical analysis detected a SE-induced increase in chemokine KC/GRO levels in ipsilateral retina (f), but no changes in the contralateral eye (g). Representative pictures and intensity measurements in the IPL of cytokine IL-1β (h), IL-6 (i), and IL-4 (j) immune staining showed increased levels of IL-1β only. Confocal images of Iba1 and ED1 immunostaining of the retina (left) and orthogonal projection of an Iba1⁺ ED1⁺ cell (right) (k), Iba1 and CD45 immunostaining of the retina (l), and Iba1 and NG2 immunostaining of the retina with NG2⁺ cells in higher magnification in inset (m). Data are presented as means ± SEM, n = 5 NSC and n = 5 SE for ELISA, n = 9 NSC and n = 6 SE for cell quantification and evaluation. *p ≤ 0.05 un-paired t test in (d) and (i–j), 2-way ANOVA in (e). Scale bars are 500 μm for (a) and (b), 10 μm for (c) 5 μm for (h-j), 25 μm for (k–m), and insets 3 μm for (k) and 5 μm for (m)