Modification of a Rodent Hindlimb Model of Secondary Lymphedema: Surgical Radicality versus Radiotherapeutic Ablation

Abstract

Secondary lymphedema is an intractable disease mainly caused by damage of the lymphatic system during surgery, yet studies are limited by the lack of suitable animal models. The purpose of this study was to create an improved model of secondary lymphedema in the hindlimbs of rodents with sustained effects and able to mimic human lymphedema. This was achieved by combining previously reported surgical methods and radiation to induce chronic lymphedema. Despite more radical surgical destruction of superficial and deep lymphatic vessels, surgery alone was not enough to sustain increased hindlimb volume. Radiotherapy was necessary to prolong these effects, with decreased lymphatic flow on lymphoscintigraphy, but hindlimb necrosis occurred after 4 weeks due to radiation toxicity. The applicability of this model for studies of therapeutic lymphangiogenesis was subsequently tested by injecting muscle-derived stem cells previously cocultured with the supernatant of human lymphatic endothelial cells in vitro. There was a tendency for increased lymphatic flow which significantly increased lymphatic vessel formation after cell injection, but attenuation of hindlimb volume was not observed. These results suggest that further refinement of the rodent hindlimb model is needed by titration of adequate radiation dosage, while stem cell lymphangiogenesis seems to be a promising approach.

Near-Infrared Fluorescence Imaging Directly Visualizes Lymphatic Drainage Pathways and Connections between Superficial and Deep Lymphatic Systems in the Mouse Hindlimb

“…These edematous changes have been reported previously 2 , 25 , 26 . The circumference of the hindlimb and the volume and stasis of lymph fluid were measured in order to evaluate the extent of lymph edema 20 , 27 , 28 . These parameters all increased in edematous tissue.…”

High-resolution 3D volumetry versus conventional measuring techniques for the assessment of experimental lymphedema in the mouse hindlimb

“…Many researches use conventional techniques to estimate the rodent hindlimb volume when reporting outcomes of experimental lymphedema treatment. Common parameters are the assessment of water displacement 36 , circumferential length 37 38 39 or paw thickness 7 19 . Importantly, while well established in human lymphology 40 , water displacement has been shown to yield inaccurate measurements in the mouse-tail model 41 .…”

Lymph Drainage During Wound Healing in a Hindlimb Lymphedema Mouse Model

“…Some previous studies of chronic lymphedema demonstrated that surgery alone did not have a sustained effect on the condition. 21,22 In this study, a hindlimb lymphedema model, in which the iLN together with the associated peripheral lymph vessels and fat tissue were excised, produced acute, but not chronic, edema.…”