Studies on the vascular drainage system of the hamster buccal pouch

Because some investigators feel that the hamster buccal pouch is an immune privileged site with no lymphatic drainage, this study was done to demonstrate and further elucidate a drainage system from the pouch to the cervical nodes. Eight hamsters were injected with india ink, submucosally in the right pouch. Dissections at one or 2 days revealed ink in macrophages in the right submandibular nodes at 2 days. Histologically, the ink was noted within macrophages which aggregated around blood vessels. No lymph vessels were noted in the pouch. Six hamsters were injected with fluorochrome-labelled latex microspheres. At 2 and at 4 days the microspheres were noted in both the pouches and the ipsilateral submandibular nodes. The results indicate there is a delayed lymphatic drainage from cheek pouches to the submandibular nodes mediated by macrophages.