ALTERATIONS OF LYMPH FLOW AFTER LYMPHADENECTOMY IN RATS REVEALED BY REAL TIME FLUORESCENCE IMAGING SYSTEM

Abstract

Secondary lymphedema is one of thesequella of cancer treatment that ininadequately understood. The purpose of thepresent study is to investigate lymphedemaformation and to explore the escape routes forexcess interstitial fluid using lymphadenectomyin a rat model. In twelve Wistar rats, lymphnodes in the right inguinal and popliteal fossaswere completely removed and lymph vesselscarefully ligated. After operation, treated hindlimbs were evaluated by indocyanine greenlymphography and circumferential measurement.Both evaluations were performed fromday 3 to ten weeks. Approximately 2 to 3weeks after operation, a network-like patternof the fluorescent signal appeared around thesurgical site which then transitioned into alinear pattern in the lower abdomen. Videorecordingsidentified fluorescent flow movingfrom the lower abdomen to the ipsilateralaxillary lymph node and in some rats, thenetwork-like pattern was also observed topass transversely over the suprapubic regionto the contralateral inguinal lymph nodes.The network-like pattern on the lowerabdomen and the linear pattern to the axillaryfossa were seen continuously to the end ofobservation. Circumferential measurementsof the treated hind limbs increased initiallyand then declined over time. This imagingsystem may be useful to detect early changesin lymphatic flow before swelling occurs andfurther study is needed.