Overall architecture and pattern of lymph flow in the rat lymph node

Abstract

The immunogenic content of the afferent lymph stimulates structures in the lymph node. Thus, a better knowledge of the processes of lymph flow and filtration in the organ should help us better understand various aspects of the node's function. To gain this understanding, we analyzed the distribution of flow in rat node draining areas locally injected with a small dose of China ink. Because the lymph-flow pattern is likely related to the overall architecture of the node, we simultaneously studied its morphology. Indeed, while the different structures of the node are known, some aspects of its overall architecture need to be resolved. The present work aimed to accomplish this by an analysis of semiserial sections of nodes from various anatomical locations in normal rats; the sections were stained by the Dominici technique or silver-impregnated.With respect to their architecture, the nodes could be distinguished into those with either a discontinuous or a continuous subcapsular sinus and peripheral cortex. These are referred to here, respectively, as segmented and nonsegmented nodes. In the segmented nodes, the subcapsular sinus with the peripheral cortex is separated by "gaps," in which medullary sinuses reached the capsule. Further, a node appears to be divided into one or more "physiological compartments," each one representing a nodal area related to an opening of an afferent lymphatic.The findings on China-ink distribution indicate that the lymph-flow pattern varies in different nodes and is determined by the particular architecture of a node, i.e., the lymph flow in a given node aligns itself along the pattern of segmentation of the organ. The findings suggest that the lymph content is first held by the endothelium lining the inner wall of a restricted area of the subcapsular sinus in a concentration which decreases with the distance from the related afferent lymphatic opening. Part of the content, possibly its nonimmunogenic fraction, would later be released to flow further along the sinus. It would then be phagocytosed by the macrophage accumulation located in the portions of medullary sinuses into which the lymph enters from the subcapsular sinus. The lymph thus filtered then flows along the medullary sinuses and leaves the organ. The latter findings also indicate that a node is divided into physiological compartments, each one being stimulated by the lymph from a given afferent lymphatic opening. As the immunogenic content of the lymph can differ from one lymphatic to another, this explains the frequent variations in similar structures located in different areas of a given node. Hence, the pattern of distribution of the openings of the afferent lymphatics of a node can account for the particularities of its overall architecture and its division into physiological compartments.

Involvement of regional lymph nodes after penetration of Schistosoma mansoni cercariae in naive and infected mice

“…The parotid lymph node of the mouse exhibited the overall architecture described for the nonsegmented lymph nodes of rats (Sainte-Marie et al 1982), even regarding the distribution of mast cells (Sainte-Marie & Peng 1990). Our findings showed that schistosomula can pass through regional lymph nodes without being damaged, even in challenged mice.…”

Histological observations on rat popliteal lymph nodes after blockage of their afferent lymphatics.

“…The normal architecture of the rat lymph node has been described in detail by SAINTE-MARIE and his co-workers SIN, 1968, 1970;BELISLE and SAINTE-MARIE, 1981a-c;SAINTE-MARIE et al, 1982). A brief description of some aspects of the popliteal lymph nodes only is therefore given here.…”

The Biological Conceptualization of the Sentinel Lymph Node (Literature Review)

“…При изучении лим-фатических узлов кролика Fisher B., Fisher E. R. [5] экспери-ментально продемонстрировали, что способность к фильтра-ции отдельного узла ограничена и что для его оптимальной функции требуются последовательно выстраиваемые узлы. В работе Sainte-Marie G. et al [6] показано, что «проме-жутки» поверхностной коры могут обеспечить быстрый шунт для тока лимфы от подкапсульного синуса к мозго-вому синусу в лимфатических узлах крысы (рис. 3А).…”