FIG. 3.

Binding of endogenous immunoglobulins to astrocytes of the lesioned spinal cord. (A) Hematoxylin/eosin (HE) and luxol fast blue (LFB) stained section showing the injury epicenter at 2 weeks post–cervical spinal cord injury (cSCI). Black inset shows the area of focus in (B). Arrows indicate the gliotic scar around the developing cavity (DC), where IgG and IgM antibodies accumulate, as shown in (B). (B) Representative image of the injury epicenter (adjacent to the section shown in (A) stained for rat IgG (red), IgM (green) and counterstained with 4′,6-diamidino-2-phenylindole (DAPI). Red arrows show presence of IgM and IgG in the glial scar. White arrowheads show presence of IgG (red and yellow signal) and IgM (green and yellow signal) in the posterior white matter, and white arrows indicate presence of IgG in the anterior white matter. (C-D) Representative picture of spinal cord sections from a rat with SCI (C) and a sham control (D) at 2 weeks post-injury, stained for rat IgG immunoglobulins, glial fibrillary acidic protein (GFAP), and DAPI. IgG antibodies co-localized with astrocytes (white arrows) surrounding the DC. No co-labeling was detected in the spinal cord section of the sham rat (D). White inset in panel (C) indicates the area represented in images (E) and (F). Scale bar: 100 μm. (E-F) Sections at the injury epicenter stained for IgG, IgM, DAPI, and GFAP (E) or chondroitin sulfate proteoglycans (CSPG; F). Panel (E) shows co-localization of endogenous IgG and IgM immunoglobulins with astrocytes (white signal) acquired by epifluorescence (i) and confocal (ii) microscope. Panel (F) shows co-localization of immunoglobulins with CSPG (white signal) as imaged with an epifluorescence (i) and a confocal (ii) microscope. Scale bar 20 μm (i) and 10 μm (ii). Color image is available online at www.liebertpub.com/neu