Observation of the Primo Vessel Approaching the Axillary Lymph Node with the Fluorescent Dye, DiI

Figure 1

Visualization of the primo vascular system in the skin lymph duct between the inguinal and the axillary nodes with the fluorescent dye DiI. (a) A schematic diagram of large-caliber lymph ducts of a rat. The lymph duct between the two nodes is near the epigastric blood vessel, which is the largest and easily identifiable vessel in this area of the skin. The axillary lymph node (AN; middle upper panel) became bright due to the DiI that flowed in through the lymph duct from the inguinal node (IN; middle lower panel). The DiI was injected into the inguinal node, and it flowed up to the axillary node through the lymph duct. The arrows in the middle two panels indicate the flow direction of DiI. Mosaics of the fluorescent images of the primo vessel in the lymph duct connecting the two nodes are given in the right panel. (b) Magnified view: A primo vessel stained by DiI was clearly visible in the lymph duct whose boundary was hardly visible. The PVS-containing lymph duct was just beside a small vessel that ran parallel to the epigastric blood vessel. This image demonstrates that DiI was not strongly absorbed by the lymph wall.

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