Single Uterine Horn Research Articles

Effects of semen components on ovulation and fertilization

In pigs, transcervical infusion of seminal plasma at the onset of oestrus advances ovulation and thus improves the chance of gametes meeting during their full fertilizing competence. An animal model that allows single uterine horn infusion was used in combination with transcutaneous sonographic monitoring of ovaries. Preparative surgery involved the detachment of one uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. Transcervical infusion of 100 ml seminal plasma immediately after the detection of oestrus advanced ovulation by between 8 and 14 h on the ipsilateral ovary adjacent to the infused horn compared with the contralateral ovary. In addition, the seminal plasma infusion did not influence the LH profile compared with uterine infusion of PBS. This finding indicates that the effect is mediated by a local mechanism in the female genital tract. The advancement of ovulation depends on the time of infusion early in oestrus and is more pronounced in gilts exhibiting a long interval between the onset of oestrus and spontaneous ovulation compared with early ovulators. At 24 h after the detection of oestrus, seminal plasma was ineffective. Apparently, seminal plasma does not affect maturation and fertilizing competence of oocytes. The activity resides in a low molecular mass protein fraction and, to a far lesser extent, in seminal oestrogens. Further characterization of the active components may allow a practical application in AI.

EP21.06: Application of transvaginal three‐dimensional ultrasound OmniView and four‐dimensional hysterosalpingo‐contrast‐sonography in female infertility

To contrast transvaginal three-dimensional ultrasound free anatomy and hysterosalpingography combined with four-dimensional ultrasound. A retrospective analysis of 175 cases of infertility patients in our hospital from January 2013 to September 2017. Ultrasound examination using Voluson E8 four-dimensional colour Doppler ultrasound diagnostic instrument. Step one, routine two-dimensional ultrasound examination of the uterus and bilateral ovaries. Step two, start the three-dimensional measurement program using OmniView mode, select the Line, Curve, Trace or Polyline method for the uterus in different positions, and sample The line is adjusted to the central position of the endocardium and parallel to the line of the endocardium. Step three, four-dimensional contrast-enhanced ultrasound examination. Among the 175 cases, 8 cases had intrauterine adhesions, 12 cases had uterine polyps, 1 case had single uterine horn, and 1 case had incomplete septate uterus. Four-dimensional contrast-enhanced ultrasonography revealed 46 cases of tubal obstruction. Using pathological results as the gold standard, the sensitivity, specificity, positive response rate, and negative response rate of uterine polyps diagnosed by OmniView were 91.67% (11/12), 18.75% (3/16), 4.88, and 0.1 respectively. The sensitivity, specificity, positive response rate, and negative response rate of OmniView technique for diagnosing intrauterine adhesions were 87.50% (7/8), 25.00% (3/20), 3.5, and 0.15, respectively. The total coincidence rate of laparoscopic dye-fluid assay for judging tubal patency was 95.83% (46/48). The two methods had higher consistency (Kappa=0.804, P<0.001). The combination of transvaginal three-dimensional ultrasound-free anatomy and hysterosalpingogram four-dimensional contrast-enhanced ultrasound can make a comprehensive assessment of the uterine cavity fallopian tube in a systematic examination, which is helpful for the diagnosis of clinical infertility. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Systemic administration of bone marrow-derived cells leads to better uterine engraftment than use of uterine-derived cells or local injection.

Stem cells are recruited to the uterus where they differentiate into endometrial cells and have been suggested as potential therapy for uterine injury such as Asherman's syndrome. However, it is unknown whether local intrauterine injection may result in better stem cell engraftment of the uterus compared with systemic administration, and whether uterine‐derived cells (UDCs) may confer an advantage over BM‐derived cells (BMDCs). Mice underwent local injury to a single uterine horn. Green fluorescent protein (GFP)‐expressing BMDCs, UDCs or saline (control) were injected either intravenously or locally (uterine lumen) into wild‐type recipients. Two or 3 weeks post‐transplant, uterine tissues were collected for fluorescence‐activated cell sorting (FACS) and immunohistochemistry/immunofluorescence studies. Mice injected intravenously with BMDCs or UDCs had increased GFP+ cells recruitment to the non‐injured or injured uterus compared to those injected locally. No significant differences were noted in GFP+ cell recruitment to the injured versus non‐injured horn. In addition, systemic injection of BMDCs led to greater recruitment of GFP+ cells at 2 weeks and 3 weeks compared with UDCs. Immunohistochemical staining demonstrated that GFP+ cells were found in stroma but not in epithelium or blood vessels. Immunofluorescence analysis revealed that GFP+ cells were mostly CD45‐negative, and negative for CD31 and cytokeratin, confirming their stromal identity. In conclusion, the systemic route of administration results in better recruitment of BMDCs or UDCs to the injured uterus than local injection. In addition, BMDCs recruitment to the uterus is greater than UDCs. These findings inform the development of stem cell‐based therapies targeting the uterus.

Local Effects of Pregnancy on Connexin Proteins That Mediate Ca 2+ -Associated Uterine Endothelial NO Synthesis

Uterine artery adaptations during gestation facilitate increases in uterine blood flow and fetal growth. local expression and distribution of uterine artery connexins play roles in mediating in vivo gestational eNOS activation and NO production. We established an ovine model restricting pregnancy to a single uterine horn and measured uterine blood flow, uterine artery shear stress, connexins 37/43, and P(635)eNOS protein levels in uterine artery and systemic artery (omental and renal) endothelium and connexins in vascular smooth muscle. Uterine blood flow and shear stress were locally (unilaterally) and substantially elevated by gestation. During pregnancy, uterine artery endothelial gap junction proteins connexins 37/43 were locally regulated in the gravid horn and elevated 10.3- and 25.6-fold; uterine artery endothelial P(635)eNOS and total eNOS were elevated 3.3- and 2.9-fold; whereas uterine artery vascular smooth muscle connexins 37/43 were locally elevated 12.5- and 5.9-fold, respectively. Less pronounced changes were observed in systemic vasculature except for significant pregnancy-associated increases in omental artery vascular smooth muscle connexin 43 and omental artery endothelial P(635)eNOS and total eNOS. Gap junction blockade using connexin 43, but not connexin 37-specific Gap peptides, abrogated uterine artery endothelial ATP-induced Ca(2+)-mediated NO production. Thus, uterine artery endothelial connexin 43, but not connexin 37, regulates Ca(2+)-mediated NO production required for the vasodilation to accommodate increases in uterine blood flow and shear stress during healthy pregnancies.

Glucosamine Inhibits Decidualization of Human Endometrial Stromal Cells and Decreases Litter Sizes in Mice1

Embryo implantation in the uterus depends on decidualization of the endometrial stromal cells (ESCs), and glucose utilization via the pentose phosphate pathway is critical in this process. We hypothesized that the amino sugar glucosamine may block the pentose phosphate pathway via inhibition of the rate-limiting enzyme glucose-6-phosphate dehydrogenase in ESCs and therefore impair decidualization and embryo implantation, thus preventing pregnancy. Both human primary and immortalized ESCs were decidualized in vitro in the presence of 0, 2.5, or 5 mM glucosamine for 9 days. Viability assays demonstrated that glucosamine was well tolerated by human ESCs. Exposure of human ESCs to glucosamine resulted in significant decreases in the activity and expression of glucose-6-phosphate dehydrogenase and in the mRNA expression of the decidual markers prolactin, somatostatin, interleukin-15, and left-right determination factor 2. In mouse ESCs, expression of the decidual marker Prp decreased upon addition of glucosamine. In comparison with control mice, glucosamine-treated mice showed weak artificial deciduoma formation along the stimulated uterine horn. In a complementary in vivo experiment, a 60-day-release glucosamine (15, 150, or 1500 μg) or placebo pellet was implanted in a single uterine horn of mice. Mice with a glucosamine pellet delivered fewer live pups per litter than those with a control pellet, and pup number returned to normal after the end of the pellet-active period. In conclusion, glucosamine is a nonhormonal inhibitor of decidualization of both human and mouse ESCs and of pregnancy in mice. Our data indicate the potential for development of glucosamine as a novel, reversible, nonhormonal contraceptive.

Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction

Fetal intrauterine growth restriction (IUGR) results in abnormal cardiac function that is apparent antenatally due to advances in fetoplacental Doppler ultrasound and fetal echocardiography. Increasingly, these imaging modalities are being employed clinically to examine cardiac function and assess wellbeing in utero, thereby guiding timing of birth decisions. Here, we used a rabbit model of IUGR that allows analysis of cardiac function in a clinically relevant way. Using isoflurane induced anesthesia, IUGR is surgically created at gestational age day 25 by performing a laparotomy, exposing the bicornuate uterus and then ligating 40-50% of uteroplacental vessels supplying each gestational sac in a single uterine horn. The other horn in the rabbit bicornuate uterus serves as internal control fetuses. Then, after recovery at gestational age day 30 (full term), the same rabbit undergoes examination of fetal cardiac function. Anesthesia is induced with ketamine and xylazine intramuscularly, then maintained by a continuous intravenous infusion of ketamine and xylazine to minimize iatrogenic effects on fetal cardiac function. A repeat laparotomy is performed to expose each gestational sac and a microultrasound examination (VisualSonics VEVO 2100) of fetal cardiac function is performed. Placental insufficiency is evident by a raised pulsatility index or an absent or reversed end diastolic flow of the umbilical artery Doppler waveform. The ductus venosus and middle cerebral artery Doppler is then examined. Fetal echocardiography is performed by recording B mode, M mode and flow velocity waveforms in lateral and apical views. Offline calculations determine standard M-mode cardiac variables, tricuspid and mitral annular plane systolic excursion, speckle tracking and strain analysis, modified myocardial performance index and vascular flow velocity waveforms of interest. This small animal model of IUGR therefore affords examination of in utero cardiac function that is consistent with current clinical practice and is therefore useful in a translational research setting.

Challenges in the diagnosis and management of interstitial and cornual ectopic pregnancies

Interstitial ectopic pregnancy is a term loosely used in the literature to describe three different entities. The first is the true interstitial ectopic pregnancy, which occurs in the interstitial or intramural segment of the Fallopian tubes. The term cornual ectopic pregnancy should be reserved for pregnancy in women with a single uterine horn, a bicornuate uterus, or a septate uterus. Angular pregnancy is a term that is rarely used and should be limited to a pregnancy in one of the angles of the uterus, but not inside the Fallopian tube. Historically, interstitial pregnancy was considered safe to manage conservatively until over 12 weeks because of the delayed risk of rupture as a result of the protection offered by the muscle of the uterus. However, over the last decade evidence now suggests that early rupture is not uncommon. The management of an interstitial pregnancy should be ascertained by ultrasonography, particularly three-dimensional ultrasonography. Depending on the size and viability of the pregnancy, management should be planned accordingly. Laparoscopic management is ideal for surgeons comfortable with the principles of laparoscopic surgery and suturing. However, laparotomy is a suitable alternative that will always provide a safe outcome. Adequate suturing of uterine cornua could prevent the risk of rupture during subsequent pregnancies. Minimizing blood loss during and after surgery is a priority.

Local Uteroplacental Influences are Responsible for the Induction of Uterine Artery Myogenic Tone during Rat Pregnancy

Uterine artery constrictor responses to elevation of intraluminal pressure (myogenic tone) are considerably enhanced in late pregnant rats, although the underlying causes remain unknown. A single uterine horn ligation model was used to differentiate local from systemic influences, and to test the hypothesis that factors associated with the site of placentation, rather than systemic hormonal changes, are primarily involved in the induction of this adaptive process. Radial uterine arteries were dissected from the gravid and nongravid uterine horns of late pregnant rats, cannulated, and pressurized. Changes in arterial diameter and smooth muscle [Ca(2+)](i) in response to the elevation of intraluminal pressure were studied using intact and endothelium-denuded arteries loaded with the ratiometric Ca(2+)-sensitive dye fura-2. Elevations of pressure from 10 to 60 and 100 mm Hg resulted in passive arterial distention of arteries from nongravid horns with a minor change in [Ca(2+)](i). In contrast, arteries from gravid horns developed myogenic tone associated with a significant elevation in [Ca(2+)](i). Synchronous oscillations in [Ca(2+)](i) and lumen diameter were frequently observed in vessels from gravid horns. Endothelial denudation augmented tone in the gravid horn but did not uncover myogenic tone in vessels from the nongravid horn. In summary, pregnancy-associated uterine artery myogenic behavior is due to an upregulation of calcium-handling mechanisms, occurs independently of the endothelium, and is induced by local uteroplacental influences.

Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

The phosphatidylinositol 3-kinase (PI3K) signal transduction pathway is a well known mediator of cell growth, proliferation, and survival signals. Whereas the expression and function of this pathway has been documented during mammalian development, evidence demonstrating the physiologic importance of this pathway in murine preimplantation embryos is beginning to emerge. This study demonstrates that inhibition of the PI3K pathway leads to the induction of apoptosis in both murine blastocysts and trophoblast stem cells. The apoptosis induced in both model systems correlates with a decrease in the expression of the glucose transporter GLUT1 at the plasma membrane. In addition, blastocysts cultured in the presence of the PI3K inhibitor LY-294002 display a decrease in both 2-deoxyglucose uptake and hexokinase activity as compared with control blastocysts. To determine the impact of PI3K inhibition on pregnancy outcome, embryo transfer experiments were performed. Blastocysts cultured in the presence of LY-294002 demonstrate a dramatic increase in fetal resorptions as compared with control embryos. Finally, we demonstrate that impairment of glucose metabolism via iodoacetate, a glyceraldehyde-3-phosphate dehydrogenase inhibitor, is sufficient to induce apoptosis in both blastocysts and trophoblast stem cells. Moreover, blastocysts treated with iodoacetate result in poor pregnancy outcome as determined by embryo transfer experiments. Taken together these data demonstrate the critical importance of the PI3K pathway in preimplantation embryo survival and pregnancy outcome and further emphasize the importance of glucose utilization and metabolism in cell survival pathways.

Studies on a local effect of boar seminal plasma on ovulation time in gilts.

Previous studies showed that intrauterine infusion of seminal plasma at the onset of oestrus could advance ovulation in pigs, possibly to enhance the chances of fertilization by optimizing the chronological events of fertilization. This effect has been attributed to a local unilateral mechanism whereby infusion into a single uterine horn advances ovulation in the adjacent ovary. The present study was designed to elucidate possible mechanisms of local signal transduction. In a series of five experiments using 43 gilts, the ovarian response was investigated after infusion of seminal plasma at different sites of the female reproductive tract. The time of ovulation was detected sonographically at 4- or 2-h intervals. Single uterine horn infusion of 100 ml seminal plasma advanced ovulation on the ipsilateral ovary by 9.3 h (mean) compared with the contralateral ovary. Dissection of the ipsilateral isthmus abolished the unilateral seminal plasma effect. Unilateral infusion of 50 microliters or 1 ml seminal plasma or 50 microliters of the concentrated 1-10 kDa fraction in the lower isthmus was ineffective. Application of 5 ml seminal plasma into the tip of a ligated uterine horn lead to 3.6 h (mean) earlier ovulation on the adjacent ovary. In contrast, the infusion of 5 ml NaCl showed no effect. Application of 5 ml seminal plasma in the middle of the uterine horn between two ligatures was ineffective. It is concluded that, for the transduction of the local signal involved in the advancement of ovulation, contact of seminal plasma with the epithelium of the utero-tubal junction is essential.

LH profile and advancement of ovulation after transcervical infusion of seminal plasma at different stages of oestrus in gilts.

The influence of a transcervical infusion of seminal plasma on preovulatory LH profiles and the advancement of ovulation after seminal plasma infusion for different times during oestrus were investigated using the single uterine horn infusion technique (Mariensee model), in combination with transcutaneous sonographic monitoring of the ovaries. Preparative surgery in 23 German Landrace gilts comprised the detachment of the left uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. In six gilts fitted with a permanent jugular vein catheter the patent horns were administered a transcervical infusion of seminal plasma (n = 5 cycles) or PBS (n = 4 cycles) immediately after the detection of oestrus by a teaser boar. In addition, 17 non-catheterized gilts received infusions of seminal plasma either 0 h (n = 3 gilts), 16 h (n = 7 gilts) or 24 h (n = 7 gilts) after the detection of oestrus. Seminal plasma infusion at the onset of oestrus provoked ovulation in the ipsilateral ovary of the treated horn 8.5 +/- 0.9 h earlier than in the contralateral (control) ovary. Seminal plasma did not influence the LH profile compared with PBS (P > 0.05), but shortened the interval between the LH peak and ipsilateral ovulation to 23.4 +/- 4.0 h compared with 31.8 +/- 3.4 h in the contralateral ovulation (P < or = 0.01). Infusion 16 h after the onset of oestrus reduced the effect to 4.6 +/- 3.8 h with a wide range of 0-8 h (P < 0.01). The effect was more pronounced in gilts with long intervals between the onset of oestrus and contralateral ovulation compared with earlier ovulation on the control ovary. Seminal plasma infusion less than 16 h before contralateral ovulation and 24 h after the detection of oestrus had no effect. It is concluded that transcervical infusion of seminal plasma early in oestrus synchronizes the variable intervals between the onset of oestrus and ovulation in sows by a locally active mechanism.

Experimental growth retardation produced by transient period of uteroplacental ischemia in pregnant Sprague-Dawley rats

Introduction of experimental growth retardation, which was based on the hypothesis of uteroplacental postischemic hypoperfusion, was attempted by a transient period of uteroplacental ischemia in dated-pregnant Sprague-Dawley rats. On day 17 of gestation right uterine horn circulation was occluded for 5 to 60 minutes in 35 dams. The fetuses were delivered by cesarean section and studied on day 21 of gestation. For each experiment the fetuses in the right horn served as the ischemia group and those in the left horn were used as the control group. Statistical analysis by Wilcoxon signed-rank test demonstrated a significant decrease in the fetal weights and in the liver-to-body weight ratios, in contrast to an increase in the brain-to-body weight ratios in the 60-minute ischemia group, compared with those in the control group. This ischemia resulted in a 14% incidence of fetal deaths. Ischemia of a single uterine horn circulation in pregnant rat for 60 minutes should readily serve as a suitable model for asymmetric intrauterine growth retardation.

Multiple factors determine the sex ratio of postpartum-conceived norway rat litters

When Norway rat litters are nursed communally, postpartum-conceived litters born asynchronously are female biased at birth. To determine if one or more mechanisms produced this sex ratio bias, we studied litters conceived at a postpartum estrus, and systematically varied the presence or absence of a litter suckling during gestation. Four different factors biased the sex ratio of postpartum-conceived litters. Postpartum condition, implantation in a single uterine horn, and very large litter size favored the birth of female pups. The presence of suckling pups during gestation, on the other hand, brought the sex ratio up to parity. Each factor operated at or before implantation, and apparently did so asymmetrically in the two horns of the uterus. Thus, a litter's sex ratio at birth, even a sex ratio of parity, can be the result of multiple mechanisms of bias, some working in opposition to each other. Theories of sex ratio biasing must incorporate multiple mechanisms rather than focusing on single mechanisms within a given species.

TRANSUTERINE MIGRATION AND SPACING OF BOVINE EMBRYOS DURING GONADOTROPIN-INDUCED MULTIPLE PREGNANCY.

AbstractUnilaterally ovariectomized and intact cattle were injected with 1,500 i.u. gonadotropins to induce superovulation, inseminated at estrus and autopsied 30 to 60 days post ovulation. The allantochorion was dissected in situ and the viability and position of embryos in utero measured. There was no difference between the intact and unilaterally ovariectomized animals in the number of corpora lutea. One to ten embryos were recovered per cow; intact animals had more embryos than the ovariectomized ones. One to two embryos migrated per uterine horn; the percentage of transuterine migration was lower in the intact animals than in the ovariectomized ones. In unilaterally ovariectomized and intact animals, a single uterine horn could sustain only one or two embryos. When the uterine horn contained one embryo, the embryo occupied the middle or upper two‐thirds of the horn. With the increase of the number of embryos the sites of embryos were unevenly spaced and overcrowded. This phenomenon led to a high rate of fetal mortality especially when the uterine horn contained more than two fetuses and transuterine migration failed to occur. The results are discussed in relation to endocrine mechanisms and species differences as they affect uterine contractions.

The use of serum gonadotropin (P.M.S.) in the induction of twin-pregnancy in the cow

The use of serum gonadotropin (P.M.S.) in the induction of twin-pregnancy in the cow

Distribution of ova in the rat uterus.

Both ovaries of female rats were exteriorized and, with the remainder of the rat in a protective lead shield, were subjected to 800 r of x rays at 60 days of age. Comparable irradiation was given to only the left ovary in other animal and some of these were unilaterally castrnted by the removal of the right ovary. In others, unilateral ovariectomy was done without irradiation of the left ovary. Other females were untreated. Distribution of implantation sites was recorded in 86 pregnancies, of which 44 were first pregnancies. Explorations revealed implantations in a total of 123 uterine horns out of a possible 162. The number of ova in a given horn varied from one to 14. The average was 7.8 ova in a single horn in 60 pregnancies produced by untreated ovaries, and 4.2 in a single horn in 63 pregnancies produced by irradiated ovaries. Although irradiation reduced the average number of implanting ova, the distribution patterns in those uteri supplied by irradiated ovaries were not affected. This reduction resulted in 27 uterine horns having only one or two implantation sites. In contrast, owing to irradiation or to unilateral castration, the opposite ovary produced 9 or more implantations inmore » 29 pregnancies. This incidence of either a smaller or larger number of implantations in a single uterine horn is significantly greater (45%) than normal. Distribution was not related to the number of implanting ova. Slightly more than half of the uterine horns had regular spacing. Irregularities were numerous. There was a tendency for ova to implant more frequently in the cervical half of the uterus. It is suggested that distribution is dependent on random scatter at the time implantation is initiated.« less

LONG-TERM REPRODUCTIVE PERFORMANCE OF FEMALE MICE

Summary. The relation of litter size to litter order was studied in eighteen normal mice (two-ovary females) and twenty-two mice in which one ovary had been removed before sexual maturity (one-ovary females). Both groups showed an initial increase in litter size, followed by a plateau period, and finally a period of linear decline in which the mean number of young born decreased by one in each successive litter. A survey of other published data on long-term reproductive performance in polytocous mammals shows that this pattern is the usual one among mice and rats, but that in pigs the decline in litter size in later life is much less marked. The mean number of young in the first litter was not significantly different in the two groups. After the first litter, number of young was consistently lower in the one-ovary than in the two-ovary group, and the linear decline of litter size started sooner. The number of corpora lutea in the ovaries at autopsy, 16 weeks after the last litter had been born, was high, and the number in the remaining ovary of the one-ovary animals did not differ significantly from the number in both ovaries together in the two-ovary group. We conclude that the lower mean litter size in the one-ovary group during the plateau period is an effect of prenatal mortality due to the presence of double the normal number of embryos in a single uterine horn. In both groups, the decline in litter size in the second half of reproductive life, which limits the total reproductive output of the female, must be due to a factor causing increased embryonic loss rather than a diminished supply of eggs. Ageing of the uterus itself is probably involved, leading to increased embryonic mortality both at and after implantation. The earlier onset of the decline in one-ovary females would then be due to overloading and premature ageing of the single functional uterine horn. In the pig, the regulation of total reproductive output is probably not primarily uterine.