Histoarchitectonics Of The Parenchyma Of Lymph Nodes Of Mammals With Different Structure Of Intranodal Lymphatic Channel

Abstract

P.N. Gavrilin, E.G. Gavrilina, V.V. Evert

The article analyzes the features of the histoarchitectonics of the lymph nodes of the bull (Bos taurus) and the pig (Sus scrofa domestica), depending on the type of structure and localization of the intranodal lymphatic channel. We studied somatic (Limphonodi (L.) cervicales superficiales) and visceral (L. jejunales) lymph nodes of clinically healthy mature male bulls and swine (16 and 6 months old, respectively). A complex of classical histological techniques was used, as well as the method of impregnating sections of lymph nodes with silver nitrate, modified by the authors. The main accumulative-distribution link in the lymph nodes of the bull is the subcapsular sinus (type I lymphatic collector), and in the lymph nodes of the pig - the capsular (intratrabecular) lymphatic tanks (type II lymphatic colector). In nodes with collectors of type I, the cortex has a simple layered structure, its outer layer is formed by a compact cortical plateau (interfollicular zone), and the inner layer is formed by a complex of spherical units of the deep cortex. In nodes with collectors of type II, the cortex is layered-folded, uneven in width. Cortical folds are formed along the capsular trabeculae with intratrabecular lymphatic tanks. The cortex plateau in the layered-folded cortex is more developed at the base of the folds, and the units of the deep cortex are at their apexes, where they form clusters in the form of specific nest-shaped structures. In nodes, regardless of the type of intranodal lymphatic channel, the surface cortex (cortical plateau) is located directly under the underlying lymphatic collectors, repeating their shape, the zones of clonal proliferation of B-lymphocytes are formed along the main collector on the basis of cortical plateau and its derivative structures (on the basis of paracortical and medullary cords). The zones of proliferation of T-lymphocytes are maximally close to the main collector, separated from it by a strip of cortical plateau, form a complex of spherical thickenings, which together form a deep cortex. The stroma and parenchyma are more developed in the nodes with collectors of type II (cumulative relative volume of stroma – 9-14% and 6-10%, parenchyma – 80-87% and 70-81%, respectively), and lymphatic sinuses - in nodes with collectors of I type (13-20% and 4-6% respectively). In the parenchyma of the lymph nodes of both groups, the zones of proliferation of T-lymphocytes predominate (the centers of deep cortex units are 27-42%), as well as the zones of accumulation of plasma cells and antibody formation (medullary cords – 17-29%), the first of which are more developed in the pig, and the latter at the nodes of the bull. The cumulative relative volume of the interfollicular zone (cortical plateau) in the studied nodes does not exceed 6-11%, and the zone of clonal proliferation of B lymphocytes (lymph nodulus) is 5-14%. These zones are more developed in the lymph nodes of the pig. Paracortical cords have the minimum and practically equivalent relative volume in the nodes of both groups (3-5%). The study shows that the principles of localization of the main specialized cellular zones in the lymph nodes of the domestic bull and the pig are universal, and the histoarchitectonics of the parenchyma has a clearly expressed specificity. Features of the histoarchitectonics of the parenchyma and its quantitative characteristics are determined by the type of structure of the intranodal lymphatic channel (the character of the localization and spatial configuration of the main accumulative-distributive unit of the nodes).

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