Changes in the immunobiological reactivity of the organism of cows in the pathogenesis of mastitis

Abstract

Immunobiological aspects of the pathogenesis of mastitis of cows of the Ukrainian black-and-white breed are considered in the article. Based on the relevance of the topic, the aim of our work was to study the functional state of nonspecific immunobiological resistance and the specific immunobiological reactivity of the cows' organism during the development of mastitis. The features of the manifestation of immune reactions in the organism of animals in the development of subclinical and purulent-catarrhal mastitis have been studied. Clinical and experimental studies were conducted in Ukrainian farms (Khmelnytsky and Vinnytsia region). Laboratory studies were carried out in the specialized laboratory of immunology of animal reproduction of the Faculty of Veterinary Medicine of the Podilsky State Agrarian and Technical University (Ukraine). Three groups of animals were formed to conduct clinical and experimental studies. As a result, it was found that subclinical mastitis of cows is accompanied by a change in the immunobiological reactivity.  Purulent-catarrhal mastitis in cows was manifested by significant changes in the parameters of nonspecific immunological reactivity. The pathological process was accompanied by a sharp decrease in bactericidal activity of blood serum (P < 0.01), as well as by suppression of phagocytic reactivity of immunocompetent blood cells. In parallel with this, there was an increase in lysozyme activity of blood serum (P < 0.01), which was associated with active degranulation and neutrophil lysis. Obviously, microphages actively migrate to the zone of the pathological process and exhibit active phagocytosis, which was accompanied by partial excretion of cytoplasmic lysozyme. In the peripheral blood of cows with subclinical mastitis, the number of reactive microphages increased sharply (P < 0.001). Simultaneously, the number of activated phagocytes with myeloperoxidase granules also increased in the peripheral blood (P < 0.01). Activation of intra-leukocyte lysozyme phagocytic cells was less intensive. Subclinical udder pathology was accompanied by an increase in the number of degranulated cells (P < 0.001), which is one of the specific properties of cytomorphological changes in programmed death (apoptosis). Subclinical inflammation of the mammary glands mastitis of cows was accompanied by a certain decrease in the number of T-lymphocytes (P < 0.001). Clinical and experimental studies have shown that subclinical and purulent-catarrhal mastitis of cows undergo significant changes in systemic immunity. In the pathophysiological model of subclinical and purulent-catarrhal mastitis, the functional state of the T-link of specific immunity was disturbed, the bactericidal activity of blood serum and phagocytosis were suppressed, which occurred against the background of changes in the cytochemical reactivity of phagocytic cells circulating immune complexes and molecules with an average molecular weigh.