Introduction
Over the past decade, there was an interest in the role of lymph node transplantation for tolerance induction in VCA. Currently, there are only few experimental small animal models of vascularized lymph node transplantation. Thus, reliable rodent models are needed to further investigate the mechanism and immunological impact of vascularized lymph node transplantation in the context of VCA. In this study we are introducing the vascularized cervical lymph node flap as a new model for transplantation studies.
Methods
Ten male Sprague-Dawley rats weighing 200 to 250 g were used in this study. The anatomic features of the cervical lymph nodes were explored. Anatomic dissections were performed and lymph node containing flaps were harvested from the cervical region based on the common carotid artery and jugular vein. Methylene blue dye was injected into the arterial pedicle. Lymph nodes were identified, and their structures was confirmed by histological evaluation. Indocyanine-green angiography was used to confirm perfusion of the lymph node flap.
Results
The length of the vascular pedicle was in a range between 2.5 to 3 cm. Adequate methylene blue dye perfusion and venous perfusion were observed in the flap after injection. The dye disseminated evenly and stained all lymph nodes included in the flap, confirming that the harvested lymph node flap has a well-established vascular network. There were 5 to 6 lymph nodes observed in the single flap. Perfusion of the flaps was demonstrated by indocyanine-green angiography.
Conclusions
To the best of our knowledge this is the first study describing the vascularized cervical lymph node flap in rats. We have demonstrated good flap perfusion by indocyanine-green angiography and confirmed the presence of a high number of lymph nodes (5–6) per flap. This cervical lymph node flap can be used for different applications including transplantation and lymphedema studies as well as studies testing mechanism of immunological tolerance induction and rejection.