SHORT TIME EFFECTS OF RADIOTHERAPY ON LYMPHATIC VESSELS AND RESTORATIVE LYMPHATIC PATHWAYS: EXPERIMENTAL APPROACHES IN A MOUSE MODEL

Radiotherapy (RT) is an importantcomponent in the therapeutic approach tooncologic conditions. This study presents theinvestigative results on the impact of RT onlymphatic vessels and on the regenerativeresponse of the lymphatic system in a mousemodel. We first irradiated 3 groups of ten miceusing brachytherapy in a single treatmentof 20 Gy. We then performed morphologicalexamination of the irradiated lymphaticvessels using an in vivo microscopic transilluminationtechnique at 2, 4, and 6 weeks.Next we evaluated lymphatic flow usinglymphoscintigraphy and in vivo microscopy at6 to 11 weeks in: 10 additional mice followingirradiation as above (IR), in 10 mice followingincision of a lymphatic vessel (I), and in anon-treated control group of 10 mice (N).Intact lymphatic vessels were observed in allmice at 2, 4, and 8 weeks following the singledose of radiotherapy in the first group of miceand normal lymphatic flow was fully restoredin the irradiated (IR) and incised (I) miceindicating that the reparative substitutionlymphatic pathways are functioning normally.We found that following irradiation with onedose of 20 Gy, lymphatic vessels were notvisibly damaged and also that lymphatic flowwas consistently restored and substitutivelymphatic pathways formed.