Figure 1
Sagittal brain slices from a SOD1 G93A transgenic mouse at terminal disease stage and from control wild type mice. (a) Immunohistochemistry applying anti-human SOD1 antibody (counterstaining: HE). Most prominent expression can be observed in motor-associated regions of the pons and the medulla as well as in midbrain regions, e.g. substantia nigra pars compacta and the reticular nucleus. A pronounced staining of the cerebellar molecular layer and a moderate staining of cerebellar nuclei can be seen. The Ammon’s horn CA1 region as well as the subiculum is temperately stained. In a detailed view of the medulla oblongata after conventional IHC of human SOD1 in the transgenic mouse brain tissue intense neuronal cytoplasmic staining as well as staining of the neuropil is visible (d). The edges of pathologic vacuoles are also frequently stained. In (b) a PET-blot of a sagittal brain slice from a SOD1G93A mouse after staining of human SOD1 is shown. A relatively homogeneous overall staining can be seen with areas of intense staining mainly in the brain stem. The staining is weaker compared to conventional IHC however the cytoplasmic as well as vacuole staining is preserved as it is shown at higher magnification of the medulla oblongata (e). When subjecting a PET-blot of a SOD1G93A mouse to limited protease digestion the residual tissue can be recognized and staining is left in the brain stem (c), appearing as large SOD1-positive clumps that often have skein-like structure, which is shown for the midbrain (f) and medulla oblongata (g). Controls are shown in (h-k): PET-blot of a sagittal WT mouse brain section and immunodetection with an antibody against mouse SOD1 without PK treatment (h) and after PK (i) shows that the endogenous SOD1 is not resistant to PK digestion. PET-blot of a WT mouse brain slice and immunodetection of 14-3-3 proteins without (j) and after PK digest (k) shows that even the highly expressed 14-3-3 is quantitatively degraded. Bars represent 200 μm (k), 100 μm (d, e, h, i, j), and 50 μm (f, g).