Congo red staining

Initially, we performed CR staining to identify amyloid fibrils as described previously [19, 20]. Briefly, deparaffinized sections were placed in CR working solution for 20 min then rinsed in 5–8 changes of deionized water. This was followed by staining with Gill ll Haematoxylin (Leica bio systems, Wetzlar, Germany) for 1–3 min and rinsing in three changes of deionized water. Sections were then dehydrated in two changes of 95%alcohol followed by three changes of absolute alcohol for 1 min each. Finally, sections were cleared in two changes of xylene and mounted in a xylene miscible medium. Sections were then visualized under bright and polarized light microscopy (Olympus CX 43, Shinjuku, Tokyo, Japan).