Fig. 8. Administration of Diphtheria toxin into the paws of tamoxifen-treated Flt4-CreER^T2; iDTR^fl/fl animals reduces lymphatic function as the result of secondary lymphedema development.

a Monitoring active lymphatic function in the contralateral hind limbs of the same tamoxifen-treated Flt4-CreER^T2; iDTR^fl/fl mouse 30 or 75 days after intradermal injection of PBS into one paw and Diphtheria toxin into another paw. 70 kDa Rh-D was injected into the paws and the transport of the molecule was monitored by fluorescent microscopy 90 min post Rh-D administration. Representative images are shown of 5–6 mouse hind limbs in each group. (bars, 1000 µm). Green rectangles show the magnified area which represent the area of popliteal lymph nodes. b Fluorescent intensity of popliteal lymph node of tamoxifen-treated Flt4-CreER^T2; iDTR^fl/fl mice 30 and 75 days after intradermal paw injection with PBS or Diphtheria toxin. 70 kDa Rh-D was injected into the paws and the transport of the molecule was monitored by fluorescent microscopy 90 min post Rh-D administration. Quantitative data are represented as mean and SEM in 5–6 popliteal lymph nodes in each group (two-tailed, paired T-test, P = 4.51 × 10⁻⁵ after 30 days for 6 mice and P = 0.0421 after 75 days for 5 mice). Asterisks indicate P < 0.05 compared with control.