Morphological adjustments of blood and lymph vessels of the broad ligament of ewe's uterus to local regulations of the reproductive organ functions

摘要

The paper presents the morphology and mutual topographic relations between blood and lymph vessels of the broad ligament of ewe's uterus, examined employing LM, TEM and SEM, and their presumable significance for the mechanism of counter-current transfer of hormones and other regulation agents. The experimental part of the paper constitutes an attempt to show a potential, local effect of ovarian hormones on some functional adjustments of vessels, connected with blood inflow to the uterus and ovary. The research was conducted on adult ewes during the reproductive period and seasonal anestrous, as well as 7-8 weeks after ovariectomy. The cycling ewes were used for morphological examinations, employing: vessel specimens filled with contrast medium and Microfil, corrosion casts of vessels and tissue specimens analyzed in a scanning electron microscope (SEM), histological specimens observed in a light microscope, and ultrastructure of lymph vessels studied by means of a transmission electron microscope (TEM). The experimental material collected from ewes in the oestrus cycle and ovariectomized ones (treated with estradiol benzoate or not) enabled to determine: the response of endothelial cells of uterine and mesentric arteries - on the basis of tissue specimens analyzed in a SEM; and the activity of NADPH-diaphorase (marker of nitric oxide synthase) in the endothelium of blood and lymph vessels from the area of broad ligament - in the course of histochemical examinations. Macroscopic observations of blood vessels indicate that despite certain individual differences, the oviductal branch and the uterine branch of the ovarian artery are characterized by tortuosity, which is less intensive in their case than in that of the ovarian branch. The oviductal branch and the uterine branch of the ovarian artery were situated side by side, or surrounded venous vessels. However, the arterial vessels supplying the oviduct and the anterior part of the uterine horn were net found to be located in a close neighbourhood of ovarian veins, carrying venous blood rich in ovarian hormones. It was also observed, for the first time, that the ovarian branch of the ovarian artery, most often straight in front of the ovary, becomes spiral in its medulla. Similar spiralization was also discovered in smaller ramifications emanating from the looped artery and heading for the cortical part of the ovary. The uterine artery and its small branches were straight within the mesometrium. Venous vessels, transporting blood both from the uterus and ovary, turned out to be very well developed. So were the valves. Despite their close contact with arterial vessels, supplying the ovary or the uterus, no cases of wall thickness reduction were observed in neighbouring vessels. It was found that the ovarian lymphatics situated along the mesovarium - although not numerous - split up and arrange net only in the vicinity of the ovarian branch, but also accompany the oviductal and uterine branches of the ovarian artery. Some of ovarian lymphatics, usually small and thin-walled, get in between the loops of the spiral ovarian branch of the ovarian artery. Uterine lymphatics, on the other hand, formed two lines: one - less developed - headed for the uterine artery; the other transported lymph from the central and paraoviductal parts of the uterine horn and, at the ovary level, entered the mesovarium area. The vessels of the other line, most of them thick-walled, were situated on the ventral side of the mesovarium, between its muscular layer and blood vessels. Lymph vessels emanating from the uterus and located along the mesovarium used to join gradually with one another and then with lymph vessels emanating from the ovary, to form two or three collecting vessels. Before reaching the paraortal lymph node, lymph vessels were arranged next to the ovarian artery and utero-ovarian vein. An analysis of vessel corrosion casts performed by means of a SEM proved that bigger arterial and venous