Study of the leukocyte profile in the mammary gland of lactating rats under the influence of oxytocin

During lactation, the structure of the organ and the composition of lymphoid cells change in the mammary gland. The change in the cells of the leukocyte series indicates a deep relationship between the immune system and the lactation process. The functioning of the mammary gland is under the influence of pituitary hormones and sex hormones, which change the cytological structure of the organ and the content of leukocytes in it. The studies were carried out on lactating rats. Were formed, one control group and two experimental groups of animals, 5 in each. Oxytocin was injected intraperitoneally at a dose of 0.1 ml to rats of the 2nd and 3rd experimental groups. The structure of the mammary gland and the composition of leukocyte cells were studied before the influence of oxytocin, 5 and 10 minutes after the administration of the hormone. The mammary glands were dissected and impression smears were prepared. The smears were stained and lymphoid cells were counted using optics. Under the influence of the hormones of the adenohypophysis, during the lactation period, the glandular tissue in the mammary gland replaces the adipose tissue. Insulin, growth hormone are able to increase the rate of DNA synthesis, stimulate mitotic activity, due to which the cell mass of the developing organ increases. With the development of structural components characteristic of a differentiated secretory cell, the structure of the alveolus is formed. Along with the differentiation of secretory cells in the alveolus, the formation of the functional activity of the myoepithelium occurs. A slight increase in the number of lymphocytes in the preparations of the control group of rats was revealed. Under the influence of the neurohypophysis hormone, the composition of immunocompetent blood cells changed. The introduction of intraperitoneal oxytocin, after 5 minutes, stimulated a significant increase in the number of lymphocytes, compared with the control group, from 16,20±3.42 to 37,80±2.63 (p<0.001). By the 10th minute, on the contrary, there was a significant decrease to 5,40±1.48 cells (p<0.001). Monocytes and a small number of neutrophils were also established. The lactation and pre-lactation periods directly affect the functioning of the immune system, changes in the composition of its cells in the mammary gland and their migration through the hemato-milk barrier into colostrum.

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