Lymph dynamics and passage of lymphocytes in isolated lymph nodes of rats

Abstract

Lymphocytes re-circulate between vascular and lymphatic systems. Lymphocytes enter to lymph nodes via high endothelium venules (HEV) and then escape from the nodes via efferent lymph vessels. There is, however, little information how lymphocytes pass through the lymph nodes via lymph dynamics including afferent and efferent lymph vessels. The present study thus investigated lymphatic traffic of lymphocytes in isolated lymph nodes of rats by an intravital-microscope system. Seven-week-old male Wistar rats were anesthetized with pentobarbital-Na (50 mg/kg). The mesenteric and iliac lymph nodes were isolated and then used in the present study. Lymphocytes were collected from mesenteric lymph nodes and labeled with CSFE. Afferent and efferent lymph vessels of iliac lymph nodes were cannulated in an organ chamber, while the arteries and veins were ligated. Isolated lymph nodes were circulated with Krebs-bicarbonate solution at a constant perfusion pressure. CSFE-labeled lymphocytes were selectively circulated into the lymph nodes via afferent lymph vessel. Lymphocytes lymphatic dynamics were measured through a fluorescent microscope system and a color chilled CCD-camera. CSFE-labeled lymphocytes circulated through afferent lymph vessel homed at the lymph node and did not appear to efferent lymph vessel for 6 hrs after the circulation. These results suggest that lymphocytes from afferent lymph vessels did not run through the lymph nodes for 6 hrs in vitro experiments. [Jpn J Physiol 55 Suppl:S94 (2005)]