Sperm--epithelium relationships in relation to the time of insemination in little brown bats (Myotis lucifugus)

In the present study, sperm distribution in the genital tract of the bitch following artificial insemination (AI) in relation to the time of ovulation was investigated by histology, scanning electron microscopy (SEM) and flushing. Ten bitches were inseminated intravaginally with 500 3 10 6 spermatozoa: three dogs before ovulation, four dogs during ovulation and three dogs after ovulation. Ovariohysterectomy was performed 24 h after AI. Half of the genital tract was divided into nine segments (cervix, corpus uteri, caudal, middle and cranial uterine horn (UTH), utero-tubal junction (UTJ), isthmus, ampulla and infundibulum), which were processed for histology and SEM. The contralateral UTH and uterine tube (UT) were flushed, and several sperm characteristics were assessed. Histology revealed that the spermatozoa were mainly located in the uterine glands and at the UTJ, while very few spermatozoa were detected in the UT. Insemination during ovulation resulted in higher percentages of glands with spermatozoa in the different parts of the uterus (P < 0.05). Evaluation by SEM showed higher numbers of spermatozoa in several parts of the uterus for bitches inseminated during ovulation (P < 0.05). The mean number of spermatozoa flushed from the UTH and the UT was low. No significant differences in the evaluated sperm quality parameters were found between the flushings of the UTH and the UT. In conclusion, based on our findings, the uterine glands and the UTJ might act as sperm reservoirs in the bitch and sperm transport in the genital tract is affected by the time of AI in relation to ovulation.

Section: Discussionmentioning

confidence: 98%

Sperm distribution in the genital tract of the bitch following artificial insemination in relation to the time of ovulation

Rijsselaere¹,

Soom²,

Cruchten³

et al. 2004

“…Some of these species, especially the snakes and turtles, store spermatozoa for several months, or even years, prior to fertilization. In general, mammals are only able to store spermatozoa for a few days in the female reproductive tract (Rodriguez-Martinez et al 2005, Rodriguez-Martinez 2007, although some bat species have evolved successful means of storing spermatozoa for several months over winter in the uterus or oviduct (Racey & Potts 1970, Racey 1979, Racey et al 1987. The mechanisms involved in prolonging sperm survival in the female reproductive tract have remained largely elusive, although the widely observed (Hunter 1981, Pacey et al 1995, Hunter & Rodriguez-Martinez 2004 formation of intimate associations between spermatozoa and the oviductal epithelial surface suggests that membrane-membrane contact is likely to be important.…”

Section: Introductionmentioning

confidence: 99%

Effects of HSPA8, an evolutionarily conserved oviductal protein, on boar and bull spermatozoa

Elliott¹,

Lloyd²,

Fazeli³

et al. 2009

Previous studies have shown that a soluble protein fraction derived from preparations of apical plasma membrane (APM) of the oviductal epithelium enhances the in vitro survival of mammalian spermatozoa. Here, we show that the survival enhancing property of the soluble protein fraction seems to depend significantly upon heat shock 70 kDa protein 8 (HSPA8 previously known as HSPA10). The following findings in the present study enabled us to draw this conclusion: first, using proteomic analysis, we identified a subset of 70 kDa oviductal surface proteins that bound to spermatozoa, one of which was HSPA8. Second, pre-treatment of the soluble protein fraction with anti-HSPA8 antibody reduced the 24 h (at 39 8C) sperm survival enhancement effect normally induced by the presence of 200 mg/ml soluble APM proteins. Third, complementary experiments showed that substituting the soluble protein fraction with bovine recombinant HSPA8 (0.5-2 mg/ml) also elicited the sperm survival effect. Finally, we also tested the effect of bovine recombinant HSPA8 on bull spermatozoa and found similar, dose-responsive, sperm survival promoting effects. The conserved nature of HSPA8 between mammalian species suggests that this protein may represent a common biological mechanism for the maintenance of sperm survival in the oviduct.

“…In some insectivores (according to genus), crypts in the oviductal isthmus or ampulla seem to perform the functions of temporary sperm storage or sequestration of excess number and regulated release (Bedford et al 1997a, 1997b, Bedford 2004b. Sperm storage in some bat species can be prolonged and occurs in the uterus, oviduct, and/or UTJ according to species (Krishna & Dominic 1978, Racey 1979, Racey et al 1987, Uchida & Mori 1987.…”

Section: Discussionmentioning

confidence: 99%

Selectivity in the transport of spermatozoa to oviductal reservoirs in the menstruating fruit bat, Carollia perspicillata

Rasweiler¹,

Badwaik²,

Mechineni³

2010

To better document the timing of ovulation and fertilization, female reproductive tracts were collected every 12 h from captive-bred fruit bats (Carollia perspicillata) on days 1-3 postcoitum and examined histologically. This also permitted observations on sperm transport, storage, and disposition. As the animals had previously been sexually segregated, most had been cycling and possessed menstrual uteri at the time of collection. Menstruation is periovulatory in this species. A widespread, headfirst orientation of spermatozoa to the uterine mucosa was observed in specimens apparently collected soon after insemination. Thereafter, however, this relationship was limited in most cases to the area around the entrance of each uterotubal junction (UTJ). A small number of spermatozoa also colonized the UTJs, which functioned as temporary sperm reservoirs on days 1-2. Although C. perspicillata is monovular, no consistent differences were observed between the two oviducts in the pattern of sperm storage and release. Very few sperm were ever observed in the isthmus or ampulla (the site of fertilization). Menstrual debris (including fine particulate matter) and leukocytes present in the uterine cavity in most tracts did not gain access to the UTJ with the spermatozoa. Smooth muscle and abundant elastic fibers in the wall of the intramural UTJ, as well as receptors on its luminal epithelial cells, may play roles in the selective transport of spermatozoa to the fertilization site. While some spermatozoa are phagocytosed in the uterine lumen or by epithelial cells in the UTJ, the fate of most is probably expulsion into the vagina.