The ultrastructure of the surface epithelia from the uterotubal junction (UTJ), and the adjacent tubal isthmic and endometrial regions, was studied in preovulatory oestrus gilts, either unmated or inseminated 12 h before with fresh boar semen. The simple columnar epithelium of the UTJ consisted of non-ciliated (secretory) and ciliated cells. Secretory vesicles occurred in the secretory cells, especially in inseminated gilts. Lymphocytes, monocytes and macrophages were found dispersed basally among the epithelial cells. Phagocytosis of epithelial cells undergoing apoptosis was seen throughout the UTJ at oestrus, increasing after insemination. Neutrophilic granulocytes were found in the lamina propria of the uterine component of the UTJ, but only occasionally in the epithelium. After insemination, neutrophils invaded the uterine epithelium, to actively participate in intraepithelial phagocytosis or move into the lumen, engulfing spermatozoa. Neutrophils were absent from the UTJ proper and the isthmic epithelium, irrespective of the presence of spermatozoa in the lumen. Those spermatozoa in the uterine lumen that escaped phagocytosis had severely damaged plasma membranes, whereas those in the UTJ proper--concentrated towards the deep furrows of the diverticulae--mostly showed normal sperm ultrastructure.

Radiolabelled compounds of different molecular size were used as tracers mixed with seminal plasma to investigate whether seminal plasma enters the oviducts of inseminated gilts. The substances were 125I-labelled human serum albumin for 3 gilts, 131I-labelled polyvinylpyrrolidone plus 59Fe citrate in 2 gilts and 131I-labelled human serum albumin plus 59Fe citrate in 2 gilts. The gilts were slaughtered 1 h after insemination and the radioactivity was measured in 4 parts of the oviduct, 9 parts of the uterine horns, the body of the uterus and the cervix. Different quantities of the compounds used were found in all oviducts, but there was close agreement between the distributions of the two compounds in the genital tract after simultaneous insemination. There was a difference (60-80%) in total amount of recovered radioactivity between left and right uterine horns. It is concluded that all compounds used entered the oviducts regardless of their molecular sizes.

No abstract

The distribution of spermatozoa in the uterus and oviducts in twelve gilts was determined 1 and 4 hr, respectively, after insemination of 1010 deep-frozen spermatozoa thawed in seminal plasma or in TESNaK-glucose buffer. The numbers found in the oviducts 4 hr after insemination were markedly higher when the spermatozoa were thawed in seminal plasma. Different theories are advanced concerning the mode of action of the seminal plasma in this respect.

No abstract