Interactions of the uterus and semen

Abstract

SummaryAt the time of breeding, large numbers of spermatozoa enter the ulerus. Only a small proportion of them are transported to the oviducts, The majority of the sperms IS to become destroyed. By some unknown mechanisms, fedile spermatozoa that are at the right maturational stage are selected over others. They are rapidly transported to the oviducts by uterine contractions. Spermatozoa elicit an inflammatory reaction in the uterus which includes the chemotaxis of leukocy.tes, The intensity of inflammation depends on semen concentration and/or presence or absence of seminal plasma. Seminal plasma suppresses inflammation and leukocyte chemotaxis. Live and dead sperm provoke a similar inflammatory response. Neutrophils and macrophages phagocytize spermatozoa. Sperm remnants are removed by lymphatics and through the open cervix, driven by uterine contractions. Although only one spermatozoa fedilizes the egg, the presence of several others is required. Even dead spermatozoa seern to fulfill this task.

The influence of early postbreeding uterine lavage on pregnancy rate in mares with intrauterine fluid accumulations after breeding

“…This is a physiological reaction against foreign material; in this case, semen, bacteria and semen extender (if artificial insemination is performed), entering the uterus (Hughes and Loy 1975;Kenney et al 1975;Pycock and Allen 1990;Kotilainen et al 1994;Troedsson et al 1995c;Katila 1997;Troedsson 1997). This is a physiological reaction against foreign material; in this case, semen, bacteria and semen extender (if artificial insemination is performed), entering the uterus (Hughes and Loy 1975;Kenney et al 1975;Pycock and Allen 1990;Kotilainen et al 1994;Troedsson et al 1995c;Katila 1997;Troedsson 1997).…”

“…Breeding or inseminating a mare induces an immediate inflammatory response in the uterus. This is a physiological reaction against foreign material; in this case, semen, bacteria and semen extender (if artificial insemination is performed), entering the uterus (Hughes and Loy 1975;Kenney et al 1975;Pycock and Allen 1990;Kotilainen et al 1994;Troedsson et al 1995c;Katila 1997;Troedsson 1997). In most mares this inflammation clears within 1 or 2 days (Watson and Nikolakopoulos 1996).…”

Effect of oxytocin and seminal plasma treatment on uterine contractile activity and pregnancy rates in subfertile mares

“…The samples obtained at that time may show the period of elimination of PMNs or a persisting endometrial inflammation, rather than the acute immune response. Already 30 min after insemination PMNs are found in the uterus and the acute post breeding inflammation peaks between 8 and 24 h while most of the PMNs are gone by 48 h (Katila 1995(Katila , 1997.…”

Exceptionalism is not exceptional in relation to sexual and reproduction mechanisms: Contrasts of human and animal sexuality

“…Second, what was not revealed or realized by these authors is that each of the species they listed (rat, cow, dog, horse, rabbit, macaque, and pig) have distinct differences in their coital mechanisms of reproduction compared to those in the human female, as is so often the case in physiological mechanisms the devil is in the detail. In rats, the female goes into lordosis and immobility while spermatozoa are ejaculated directly into the uterine cavity, similarly in the horse during coitus the tip of the male's penis is thought to penetrate the oestrus‐opened cervix and delivers the semen directly into the uterus (Thomas, ) while both rat and horse have a vaginal “gel plug” that forms from the ejaculate to prevent sperm leakage and further sperm from entering the uterus, most stallions bite the mare's buttocks, flanks and legs before mounting (England, ), in dogs the male penis is locked into the female vagina during coitus and ejaculation (genital lock) and semen is ejaculated into the uterus and vagina while in macaques this locking happens after ejaculation (Puts and Dawood, ) which creates the linking coupled behavior of “pair sit” (Slob and van Der Werff Ten Bosch, ), in rabbits ovulation is induced by the cervical stimulation during coitus and vaginal contractions are needed to transport the semen through the cervix into the uterus (Katila, ), finally, in swine the penis is screwed into the females' cervix where it is locked during the injection of 150–500 mL of semen over 15 min into the uterus which is then transported onwards by muscle contractions taking 2 hr to arrive at the fallopian tube. It is not too difficult to appreciate that none of these processes are to be found in our human coital scenario.…”