[Ultrastructural changes in the uterine epithelium and in the immunocompetent cells of the lymph nodes draining the uterus during pregnancy in swine].

The studies were carried out with both nonpregnant sows aged 1-2 years and pregnant sows from the 30th to the 40th day and on the 60th, 90th, and 100th day of gestation. Three types of cells were found in the epithelium covering the uterus of nonpregnant sows--with kinocilia and microvilli at the apical pole, with microvilli only, and with no microvilli and kinocilia. During pregnancy the ultrastructure of the epithelium were subjected to essential changes which consisted chiefly in increasing the compactness of microvilli, the amount of lysosomes at the apical part, and the basal deposition of fatty globules in some of the cells. The basal membrane on which the epithelial cells lay became considerably thicker. The draining lymph nodes showed a clear trend toward increasing the number of lymphocytes and cells of the plasmatic order. The ultrastructure of the plasmatic cells and lymphocytes spoke of enhanced processes of synthesis.