Preclinical deposition of pathological prion protein PrP^Sc in muscles of hamsters orally exposed to scrapie
J. Clin. Invest. Achim Thomzig, et al. 113:1465 doi:10.1172/JCI21083 [Go to this article.]

Figure 3
Intramuscular location of PrP^Sc in terminally ill 263K scrapie hamsters visualized by PET blotting and IHC. (A) PET blot from M. triceps brachii. Individual muscle fibers display deposition of PrP^Sc predominantly subsarcolemmal in the region of the fiber surface, but PrP^Sc is also scattered within fibers (arrowheads). At some myofibers PrP^Sc immunostaining exhibits a structural pattern reminiscent of neuromuscular junctions (asterisk and inset). Only minor PrP^Sc deposits are visible within nerve fascicles (arrow). (B) Adjacent section to A, stained with H&E; arrow: nerve fascicle. (C) Adjacent section to A, immunohistochemically stained with mAb 3F4 without detectable PrP^Sc deposition; arrow: nerve fascicle. (D) PET blot from M. masseter; PrP^Sc in adjacent as well as topologically distant muscle fibers (arrowheads), distributed in a pattern reminiscent of that expected for motor units innervated by individual neurons in the spinal cord. Note: Tangentially cut muscle fiber (rhomb) with strong granularly scattered immunolabeling. Reproduction in higher magnification (inset: photomicrograph from a different section) illustrates prominent subsarcolemmal localization of PrP^Sc deposition in myofibers. (E) PET blot from lingual muscle; distinct endoneural PrP^Sc accumulation in nerve fascicles (arrows). One fascicle (asterisk) is reproduced in higher magnification in the inset. The intensity of PrP^Sc deposition in muscle fibers of the tongue (arrowheads) seems to be stronger than that observed in other muscles. (F) Sample from lingual muscle immunohistochemically stained with mAb 3F4; granular immunostaining illustrates subsarcolemmal as well as scattered PrP^Sc deposition in muscle fibers (arrowheads; inset: higher magnification of fiber marked by an asterisk). Scale bars in A–F, 100 ∝m.