Lymphatic endothelial cell damage following afferent DEFINITY® injection.

<p>4-month-old TNF-Tg and WT mice received a footpad injection of DEFINITY® or saline, and were subjected to US imaging as described in Materials & Methods. 4 weeks later, the injected footpad received an injection of Evan's blue dye to identify the lymphatic vessels afferent to the PLN, which were harvested and processed for transmission electron microscopy. Representative images are shown to illustrated the endothelial cells (EC); smooth muscle cells (SMC); and lumen (L) of the lymphatic vessel. Note the damaged lymphatic vessel in the DEFINITY^® injected mice (A,B), as evidenced by the cell detachment (arrows in A), and obviously large vacuoles and intraluminal protrusions (arrow heads in B), as well as the atrophic appearance of the smooth muscle cell (B). In contrast, the lymph vessels exposed to saline showed attached endothelial cells and minor vacuoles (arrow head in C), but also have obvious intraluminal protrusions (arrow head in C). WT lymphatic vessel displayed and intact endothelial cell layer without vacuoles and no intraluminal protrusion (D).