Journal: Journal of Neuroinflammation

Article Title: Interleukin-1α expression precedes IL-1β after ischemic brain injury and is localised to areas of focal neuronal loss and penumbral tissues

doi: 10.1186/1742-2094-8-186

Figure Lengend Snippet: IL-1α is expressed by microglia localized to focal neuronal and BBB injury 24 h after MCAo . Images are coronal sections from brains of C57BL6/H and CX3CR1-GFP +/- mice 60 min MCAo and 24 h reperfusion. Widefield images show IL-1α-expressing (red), GFP positive (green) microglia in ipsilateral (Ai), not contralateral (ii) amygdala 24 h after MCAo in a CX3CR1-GFP +/- mouse. IL-1α immunohistochemistry with cresyl violet co-staining localises IL-1α expressing microglia to the peri-infarct zone in thalamus (Bi) and cortex (Bii) of a C57BL6/H mouse. Focal IgG staining (red) co-localized with IL-1α positive microglia (green) in the ipsilateral cortex of a C57BL6/H mouse (Ci). No IgG or IL-1α staining detected in the contralateral cortex (Cii). IL-1α positive microglia detected in larger areas of IgG staining in the ipsilateral (Ciii), but not contralateral (Civ) hemisphere. Co-localization of IL-1α positive microglia (red) with areas of neuronal loss (blue) in a C57BL6/H mouse (D). Occasional IL-1α positive microglia also found in areas where neurons were morphologically intact (D, inset). Confocal images (E) are maximum Z projections (Ei, iii) and confocal slices at the level of the nucleus (Eii, iv) of IL-1α expressing, GFP positive microglia in a CX3CR1-GFP +/- mouse. Cells with (Ei, ii), and without (Eiii, iv) nuclear IL-1α. Nuclear fluorescence intensities for IL-1α and GFP were quantified from confocal images, and the fold enrichment of IL-1α and GFP in microglial nuclei was calculated in comparison to whole cell fluorescence (F). All images are representative of n ≥ 3 mice. Quantification is of n = 4 CX3CR1-GFP +/- mouse brains, with each data point representing an individual cell, n ≥ 30 cells per brain.

Article Snippet: Staining of coronal brain sections from C57BL6/H mice (Figure ) and CX3CR1-GFP+/- mice (not shown) 24 h after MCAo for IL-1α and IgG (BA-2000, Vector Labs, biotinylated horse anti-mouse IgG, 2 μg/mL; S-32356, Invitrogen, Alexa 594 conjugated streptavidin, 5 μg/mL) revealed that IL-1α expressing cells co-localized to areas of focal BBB damage, mainly near the penumbral regions of the ipsilateral hemisphere (Figure ).

Techniques: Expressing, Immunohistochemistry, Staining, Fluorescence