Translocation of particles from lung lobes or the peritoneal cavity to regional lymph nodes in beagle dogs

Abstract

Knowing the clearance pathways from the lung for inhaled materials is important to our understanding of the kinetics of particle clearance from the lung and other defense mechanisms, such as development of immune reaction to inhaled antigens. To determine the pathways and amounts of particles translocated to regional lymph nodes, radiolabeled fused aluminosilicate particles were instilled into specific lung lobes or injected into the peritoneal cavity of beagle dogs and the dogs were necropsied 34, 182, or 365 d later. Individual lung lobes cleared particles to one or two lymph nodes, and specific lymph nodes accumulated particles from one to three lung lobes. Lymph nodes that collected particles from the lung included the left mediastinal node, left tracheobronchial lymph node (TBLN), right TBLN, left middle TBLN, and right middle TBLN. The destinations for translocated particles were primarily the nodes proximate to the tracheal bifurcation. Particles injected into the peritoneal cavity were translocated mainly to mesenteric lymph nodes and left sternal and right sternal lymph nodes, with a small percentage of the particles going also to the left TBLN.