Figure 4.
Dead endothelial cells in damaged vessels. Apoptotic cells (arrow) with pyknotic nuclei and TUNEL+ dead cells (arrow) were detected in the damaged capillaries (A, C) and small arteries (B, D) (A and B: H&E stain; C and D: TUNEL stain). TUNEL+ dead cells (arrow) were more prominent in the grafts with graft failure (E: stage 1, F: stage 2, G: stage 3; E–G: TUNEL stain). Partial loss of CD31+ or MHC class II+ staining (arrowhead) indicated endothelial cell loss in the damaged capillaries and arteries (H and J: CD31 stain; I: MHC class II stain). Arrow indicates capillaries without thrombi. Original magnifications: ×400 (A–D, H, I); ×200 (E–G, J).