title: A new preparation for visualizing lymphatic flow pathway in isolated rat lymph nodes.
abstract: BACKGROUND
  There is no reported study in which the lymphatic flow pathway in lymph nodes has been visualized and investigated in in vitro studies. The purpose of the present study is first to develop an isolated rat lymph node preparation circulated through the afferent and efferent lymph vessels in order to visualize lymphatic flow pathway within the node by using a video microscope system, and then to evaluate lymphatic flow dynamics by using fluorescence-labeled substances.
  
  
  RESULTS
  In the present study, rat iliac lymph node was isolated. The afferent and efferent lymph vessels of the lymph node were cannulated with glass micropipettes in an organ chamber, while the small-sized arteries and veins connected to the lymph node were secured with sutures. Krebs-bicarbonate solution with or without fluorescent probes [FITCdextran, mol. weight; 77,000 and/or fluoresbrite carboxylate-microspheres (FC-microspheres) mean diameter of 1 microm] was circulated through the lymph vessels of the node. The time-dependent lymphatic pathway of fluorescent probes was investigated with a video microscope system. FTIC-dextran first spread through the cortex and subsequently reached the medulla of the lymph node. A follicle-like structure became evident in the cortex. FITC-dextran appeared in the efferent lymph vessel at 109 +/- 21 sec after its circulation began, while FC-microspheres distributed in the lymph node did not emerge from the node within 20 min after their introduction.
  
  
  CONCLUSIONS
  In vitro preparations constructed in the present study will enable us to visualize the lymphatic flow pathway of fluorescent substances within the isolated iliac lymph nodes of rats in the absence of blood circulation.
authors.affiliation: Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Risuke
authors.initials: R
authors.lastname: Mizuno
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ono
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Ikomi
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohhashi
mesh_terms: D000818:Animals; D003911:Dextrans; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D005456:Fluorescent Dyes; D007082:Ileum / Q000098:blood supply / Q000166:cytology*; D008198:Lymph Nodes / Q000098:blood supply / Q000166:cytology*; D008208:Lymphatic System / Q000166:cytology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate