FIG. 10.

Large volume scanning of mouse ileum 1 and 7 days after TBI. Mice expressing GFP within neutrophils were irradiated (9.25 Gy) and sacrificed at 1 and 7 days after irradiation. The ileum was harvested, fixed in 4% paraformaldehyde, and placed in clearing solution (CUBIC1) for a week. The samples were then mounted in a prototype high-speed ribbon scanning system, and the entire ileum volumes were captured. (A) is a three-dimensional projection of the entire thickness of the ileum 1 day after irradiation. There is a small amount of autofluorescence from the blood vessels. Peyer's patches [e.g., insets denoted (B,C)] have abundant neutrophils associated with the patch. When the same patches are imaged as optical sections, it can be seen that cells are limited to the periphery of the structure (B, C). Further, it can be seen that villus structure (in common with A) is well maintained [in cross-section in (D) and longitudinal section (E)]; however, there are abundant bright spots (denoting neutrophils) within these structures. (F) is an equivalent sample to (A), the autofluorescent material within the lumen is murine chow. The notable features of the sample are the progression from healthy tissue to a complete absence of structure. Neutrophils are still present (G); however, the villi, serosa, and most of the adventitia are lost from the tissue. At this point, the ileum is extremely fragile and about to fail completely (H). Scale bars: 1 mm. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars