Non-pregnant Uterine Horn Research Articles

Study on the Pattern of Postpartum Uterine Involution in Dairy Cows

Postpartum uterine involution is necessary for the normal reproduction of dairy cows. The study aimed to investigate the pattern of postpartum uterine involution and the impact of parity on uterine involution in Chinese Holstein dairy cows. The diameter of the uterine cervix, pregnant uterine horn, and non-pregnant uterine horn were monitored using a B-mode veterinary ultrasound scanner at 5, 10, 15, 20, 25, 30, 35, and 40 days, respectively, after parturition in both multiparous and primiparous dairy cows. Meanwhile, the concentrations of hydroxyproline, E2, and IGF-1 were detected using ELISA at 5, 10, 15, 20, 30, and 40 d after parturition in both multiparous and primiparous dairy cows. Furthermore, the duration of uterine involution was compared in the multiparous and primiparous dairy cows. The results demonstrated that the diameter of the uterine cervix and the pregnant uterine horn did not decrease any further at 25 days postpartum for both the multiparous cows and the primiparous cows. Hydroxyproline levels gradually decreased with uterine involution; however, there was no significant variation in IGF-1 concentrations during uterine involution in the dairy cows. Although E2 concentrations of the peripheral plasma displayed an upward trend from day 5 to day 15 in the two groups of postpartum cows, there was no significant difference between the two groups during uterine involution. These results suggest that postpartum uterine involution was around 25 days postpartum in both the primiparous dairy cows and the multiparous Chinese Holstein dairy cows. Parity did not affect uterine involution in the postpartum Chinese Holstein dairy cows. The hydroxyproline levels of the peripheral blood may be an indicator of uterine involution in postpartum cows. Nonetheless, IGF-1 and E2 levels of the periphery blood are not associated with uterine involution in Chinese Holstein dairy cows.

Ezrin immunoexpression in trophoblast cells of the equine placenta

Ezrin expression in microcotyledons and trophoblastic cells plays an important role in vascularization and maternal-fetal exchange. Ezrin is a membrane cytoskeletal crosslinker protein that helps regulate several cytoskeletal-related functions, including cell adhesion (Souza.et.al. Research in Veterinary Science.2023. 154: 84-88). Here, we describe the histopathological findings and expression as detected by an ezrin-specific antibody in pregnant and non-pregnant uterine horns of normal equine placentas. Eighteen placentas from embryo recipient mares of the Mangalarga Machador breed were collected at delivery (n=18; age 4-8 years). All placentas were evaluated for macroscopic characteristics. As part of the histopathological evaluation, pregnant and non-pregnant horn samples underwent hematoxylin-eosin staining to grade and compare the arrangement and vascularity of microcotyledons and allantochorions. Silanized slides were immunostained with an ezrin-specific antibody (clone: H-276; rabbit polyclonal-IgG; Santa Cruz; dilution: 1:500μl; LSAB+ Dako, Carpenteria, California, USA). A sample of human breast ductal adenocarcinoma was used as the positive control. For the negative control, the primaryantibody was replaced with a primary antibody isotype. In the microscopic analysis, the microcotyledonary arrangement in the pregnant horn was more intense than in the non-pregnant horn, except for one case. In terms of vascularization, the horns did not differ in the number or intensity of vessels in the microcotyledons and allantochorion. Ezrin antibody expression in placental horns was more intense in the proximal region of the microcotyledons compared with the basal lamina of the allantochorion and was diffused throughout the microcotyledonary network. The pregnant horn showed greater ezrin expression in trophoblasts compared to the non-pregnant horn. The two horn types showed similar color intensity in most samples however, ezrin was expressed mildly in the pregnant horn, while the non-pregnant horn from the same placenta showed moderate to intense ezrin expression. These observations may reflect a way of modulating maternal–fetal exchange, because trophoblast cells have this function. In summary, ezrin was expressed in trophoblast cells located in the microcotyledons of equine placentas, suggesting that this protein may play a role at the maternal–fetal interface.

Determining the In Vitro Effects of Aqueous Elephant Dung and Fadogiaancylantha Leaf Extracts on Isolated Rat Pregnant Uterus Horns

Background: In Zimbabwe, elephant dung and Fadogia ancylantha are widely used in the third trimester of pregnancy. They are believed to facilitate childbirth because they open the birth canal during delivery. However, the effects of these medicines in pregnancy have not been investigated. This study aimed to determine the effects of elephant dung and F. ancylantha leaf extracts on isolated pregnant and non-pregnant uterine horns. Materials and Methods: Elephant dung and Fadogia ancylantha leaves were air-dried, macerated in water, filtered, evaporated and freeze dried. Uterine horns from 72 non-pregnant and 72 pregnant female Sprague-Dawley rats were used. The ‘test’ strips were separately exposed to elephant dung (20-640 mg/ml) or F. ancylantha (25-800 mg/ml) while the 'controls' received distilled water only. Effects of oxytocin on tissues exposed to these extracts were measured. Results: Elephant dung aqueous extract contracted the uterus in a dose-dependent manner whilst Fadogia ancylantha relaxed uterine tissue in a dose-dependent manner. The effects of both the Elephant dung and Fadogia ancylantha extracts were higher in pregnant uteri versus non-pregnant uteri. Oxytocin potentiated elephant dunginduced contraction, but only slightly shifted baseline upwards in tissues exposed to Fadogia ancylantha. Conclusion: Elephant dung possessed oxytoxic effects and contracted uteri in a dose-dependent manner. Fadogia ancylantha relaxed the uterus in a dose-dependent manner, suggesting that it might slow down labour progression since uterine contraction will not be occurring at a sufficient enough pace to facilitate labour and delivery. Pregnant women and health care workers need education to understand the possible effects of using these traditional medicines in pregnancy.

Macroscopic evaluation of the placenta of the alpaca (Vicugna pacos).

Macroscopic evaluation of the placenta is an essential post-partum examination in the alpaca and can be of special interest in case of abortion, premature birth or stillbirth. Since there are not many reference values regarding macroscopic properties of normal alpaca placentas, a small descriptive study was conducted. Only placentae from normally foaling alpaca mares, giving birth to healthy crias, after a full-term and uneventful gestation (±350days; range 335-360days) were taken into account (N=11). Crias weighed (±SD) 7.7±2.25kg (range 5.5-10kg), while the mean weight of the full-term placentas was 0.8±0.19kg, that is 10% of the bodyweight of the crias. The weight of the allantoamnion and chorion was 0.2±0.07kg and 0.5±0.13kg, respectively. The umbilical cord length was 8.8±2.84cm, and the length of the pregnant and non-pregnant uterine horns was 69.4±12.77cm and 54.5±6.81cm, respectively. The length of the corpus was 14.6±4.68cm, and the distance from the umbilicus to the corpus was 18.5±6.13cm. The tissue volume of the allantoamnion was 0.14±0.079L, and the chorionic volume was 0.37±0.078L. The surface area of the allantoamnion and the chorion was 87.6±15.56dm2 and 72.3±9.28dm2 , respectively. All placentas had small calcifications either around the umbilical cord alone or around the umbilicus and blood vessels of the pregnant uterine horn. These measurements could be used to macroscopically evaluate alpaca placentas, although more research is needed to extend our knowledge of macroscopic evaluation of normal and abnormal placentas.

A Novel Experimental Model of Colorectal Endometriosis

ABSTRACTPurpose: Endometriosis is a disease that affects 6–10% of the female population, mainly women of reproductive age, and causes a variety of cyclic symptoms. Deep infiltrating endometriosis and in particular bowel involvement presents a challenge for modern surgery. To date, there are no experimental animal models in this field, demonstrating experimental induction of endometriosis directly attached to surface of the colon imitating human colorectal endometriosis; hence, the implementation of novel pharmaceutical and surgical strategies for the management of colorectal endometriosis is mainly limited to clinical studies. Aim of the study: To investigate whether induction of colorectal endometriotic lesions in is feasible in rats. Materials and Methods: Twenty, female, adult, non-pregnant Sprague Dawley rats sustained uterine horn resection, which was then placed around the rectum of the rat with the endometrial surface in direct contact with the bowel serosa and approximated in the serosal surface of the colon with two sutures. Results: Two weeks following, surgery rats were euthanized and the bowel was surgically explored. The presence of a cystic lump at the site of the surgical intervention was evaluated macroscopically and microscopically. Histopathology documented the presence of cystic endometriosis. The endometriotic focus was adherent to the bowel wall by large fibrous nodules with concomitant replacement of part of the outer longitudinal muscle layer. Conclusions: The findings of our study support that the proposed experimental model of colorectal endometriosis is feasible, easily reproducible and may be implemented in future research in this field.

095 Comparison of expression of glucose, fructose, and cationic amino acid transporters in bovine caruncular and inter-caruncular tissue between the pregnant and non-pregnant uterine horn from days 16 to 50 of gestation

095 Comparison of expression of glucose, fructose, and cationic amino acid transporters in bovine caruncular and inter-caruncular tissue between the pregnant and non-pregnant uterine horn from days 16 to 50 of gestation

Birth of the first donkey foals after transfer of vitrified embryos

betweenmicrocotyledonary density and parity. Means s.e. for microcotyledonary density were: 3.06 1.04 in pregnant uterine horn, 2.35 0.69 non-pregnant uterine horn and 2.64 1.01 to uterine body. In conclusion, our results clearly demonstrated the impact of mare parity on placental and newborn characteristics. Regardless of the similar microcotyledonary density observed among groups, mares with more pregnancies probably increased uterine size, which enables greater fetomaternal contact, better nutrient supply, and consequently heavier foals and placenta.

Use of increasing doses of a degradable Deslorelin implant to enhance uterine involution in postpartum lactating dairy cows

Holstein cows received, subcutaneously 1 (1DESL, n = 15) or 2 (2DESL, n = 12) degradable implant containing 2.1 mg of the GnRH agonist Deslorelin or no implant (CON, n = 18) within 1.5 days postpartum (dpp). Previous pregnant (PPH) and non-pregnant (PNPH) uterine horns were determined by palpation per rectum. Cows were examined by ultrasonography at 8 dpp, 15 dpp, 22 dpp, 29 dpp, and 36 dpp (S.E. = 1 day) to record ovarian structures, cervical diameter, uterine horns cross-section and lumen diameters, myometrial and endometrial widths. Uterine tone was recorded before ultrasonography. Vaginoscopy was conducted just after ultrasonography for cervical discharge score. At 44 dpp cows were inserted with a CIDR followed 7 days later by its removal and injection of PGF 2α 8 h later, followed by the Ovsynch 10 days after for timed artificial insemination (TAI). Plasma was analyzed for PGFM daily from parturition to 14 dpp and for P 4 trice weekly until 44 dpp. Additionally, strategic blood samples were collected during the synchronization protocol to determine whether estrous cyclicity was occurring and ovulation status before and after TAI, respectively. Cows in 1DESL and 2DESL groups had more class 1 follicles ( P < 0.01), less class 2 ( P < 0.01) and class 3 follicles ( P < 0.01) compared with CON. First increase of P 4, indicative of ovulation, occurred in CON (55.5%) cows at 28 dpp (S.E. = 9 days) and in 1DESL (13.3%) treated cows at 43 dpp (S.E. = 3). Plasma concentrations of P 4 were suppressed completely in all 2DESL-treated cows before initiation of estrous synchronization. Diameters of PPH ( P < 0.01), PNPH ( P < 0.01), uterine horn lumens ( P < 0.01) were less in the 1DESL and 2DESL groups with greater uterine tone ( P = 0.07). Frequency distribution of cervical discharge categories did not differ among groups. Proportion of cows with estrous cycles and having ovulations was less ( P < 0.01) in DESL implant cows compared with CON that was to a greater ( P < 0.01) extent in the 2DESL. Treatment with Deslorelin during postpartum (1) suppressed follicular development, (2) enhanced physical involution of the uterus, (3) increased tone of the uterine wall, (4) delayed first ovulation and reduced responsiveness to a synchronization of ovulation protocol. Future research should focus in GnRH agonist delivery systems to restrict duration of treatment to optimize uterine involution and avoid a prolonged period of anovulation.

Postpartum suppression of ovarian activity with a Deslorelin implant enhanced uterine involution in lactating dairy cows

Holstein cows received, subcutaneously a non-degradable implant containing 5 mg of the GnRH agonist Deslorelin (DESL) or no implant (CON) at 2 ± 1 days postpartum (dpp). All cows were injected with PGF 2α at 9 dpp. Previous pregnant (PPH) and non-pregnant uterine horns (PNPH) were determined by palpation per rectum. In Experiment 1, cows [DESL implant ( n = 10) and CON ( n = 9)] were examined by ultrasonography to record ovarian structures (23, 30 and 37 dpp) and uterine horn and cervical diameters (16, 23, 30 and 37 dpp). Uterine tone was scored before ultrasonography. Vaginoscopy was conducted just after ultrasonography examination to assess cervical discharge and color of the external cervical os. Blood samples were collected on a weekly basis for hormonal analyses. In Experiment 2, cows [DESL implant ( n = 77) and CON ( n = 70)] were palpated per rectum and vaginoscopy at 30 dpp for scoring of uterine tone, uterine horns, cervical diameter, and discharge. Blood samples were collected only at 9 dpp. In Experiment 1, DESL-implant-treated cows had more Class 1 follicles ( P < 0.01), less Class 2 ( P < 0.01) and Class 3 follicles ( P < 0.01) and no corpus luteum (CL) formation ( P < 0.01). In CON cows, six of nine animals had visible CL at 25 ± 7 dpp. At 9 dpp plasma concentration of E 2, P 4 ( P < 0.01) and PGFM ( P < 0.05) were less in the DESL-implant treatment group. Diameter of PPH ( P < 0.01), PNPH ( P < 0.01) and cervix ( P = 0.08) were less in the DESL-implant treatment associated with greater uterine tone ( P = 0.07). The DESL-implant cows had a greater frequency of clear cervical discharge ( P = 0.09) and pink cervical os ( P = 0.06). In Experiment 2, plasma concentrations of PGFM were less at 9 dpp in DESL-implant treatment ( P < 0.01). Diameters of the PPH ( P < 0.01) and PNPH ( P < 0.01) were less and more uterine tone ( P < 0.01) in the DESL-implant treatment. Diameter of cervix and frequency of a cervical discharge score did not differ between treatments. Treatment with non-degradable Deslorelin (5 mg) implant during postpartum: (1) suppressed ovarian follicular development, (2) enhanced physical involution of the uterus and cervix, (3) increased tone of the uterine wall, (4) decreased frequency of purulent cervical discharges, and (5) reduced inflammatory processes of the reproductive tract.

Regulation of immune cells in the uterus during pregnancy in ruminants1

Pregnancy results in a change in number and function of immune cells in utero that potentially affects fetal survival and uterine defense mechanisms postpartum. These changes are driven by local signals from the conceptus as well as from hormonal changes mediated by the placenta or maternal system. In sheep, for example, macrophages accumulate in the uterine endometrium during pregnancy (Tekin and Hansen, 2004). Use of a unilaterally pregnant model, in which pregnancy is surgically confined to 1 uterine horn, has revealed that accumulation of macrophages is due to systemic signals (numbers of cells in the nonpregnant uterine horn of the unilaterally pregnant ewe higher than amounts in uteri of nonpregnant ewes) and locally produced signals (number of cells in the uterus of unilaterally ligated ewes higher in the pregnant horn than in the nonpregnant horn; Tekin and Hansen, 2004). Gamma-delta T cells also accumulate in uterine epithelium during pregnancy as a result of unidentified systemic signals (Lee et al., 1992; Majewski et al., 2001). These cells may participate in growth of the conceptus, immunosuppression, or placental detachment at parturition. One of the key regulators of uterine immune function is progesterone. In sheep, progesterone can block tissue graft rejection in utero when injected to achieve concentrations too low to directly inhibit lymphocyte proliferation (Majewski and Hansen, 2002; Padua et al., 2005). Progesterone probably inhibits uterine immune responses in sheep indirectly by inducing secretion of a member of the serine proteinase inhibitor family called uterine serpin from the endometrial epithelium. Uterine serpin can block lymphocyte proliferation in vitro in sheep (Peltier et al., 2000) and natural killer cell-mediated abortion in vivo in mice (Liu and Hansen, 1993). Uterine serpin is also present in cattle, goats, and pigs, but its role in immune function in these species has not been documented. The relevance of changes in uterine immune function to the reproductive and immune status of ruminants has not been fully established. There is evidence for immunological causes of pregnancy loss associated with cloned fetuses (Hill et al., 2002) and with mastitis (Hansen et al., 2004), but it is not known whether inappropriate recognition of alloantigens on the conceptus is an important cause of pregnancy loss. It is also possible that downregulation of uterine immune function during pregnancy can lead to a postpartum uterus with a compromised capacity for preventing establishment of infectious disease. Thus, optimal immune function in utero requires a balance between the need to maintain effective immune surveillance and effector mechanisms with the requirement that immunological responses leading to conceptus demise are minimized.

Expression of iNOS mRNA and Inhibitory Effect of NO on Uterine Contractile Activity in Rats Are Determined by Local Rather Than Systemic Factors of Pregnancy

Our purpose was to investigate whether the local or systemic factors of pregnancy are associated with inducible nitric oxide synthase (iNOS) mRNA expression and to determine the inhibitory effects of pharmacological agents that increase cGMP levels in rat myometrium. iNOS mRNA expression was determined in uterine tissues from nonpregnant rats and on day 17 of gestation in the pregnant and non-pregnant uterine horns by RT-PCR. In addition, uterine rings from the pregnant and non-pregnant uterine horns were placed in Krebs-Henseleit solution for isometric recordings of spontaneous contractions. Concentration-inhibition relationships to diethylamine/nitric oxide complex, 8-bromo-cGMP, and the selective phosphodiesterase V inhibitor were obtained. Compared to nonpregnant rats, expression of iNOS mRNA in myometrium increased during pregnancy, which was maximal on day 17, followed by a decrease on day 21 of gestation. Expression of iNOS mRNA at day 17 of gestation was greater in pregnant uterine horns than in nonpregnant ones. Maximal inhibition of phosphodiesterase V and increasing cGMP induced similar inhibition of spontaneous contractions in nonpregnant and pregnant uterine horns, while NO induced less inhibition in the former. The results suggest that the local pregnancy factor is needed for signal transduction from NO to soluble guanylate cyclase at a time when maximal expression of iNOS mRNA is evident.

Regulation of Numbers of Macrophages in the Endometrium of the Sheep by Systemic Effects of Pregnancy, Local Presence of the Conceptus, and Progesterone

Many species exhibiting hemochorial placentation experience an accumulation of macrophages in the endometrium during pregnancy. For the present study, it was tested whether macrophages also accumulate in the endometrium of the sheep, which is a species undergoing an epitheliochorial placentation. An additional objective was to determine whether regulation of endometrial macrophage number occurs via systemic or local signals and whether progesterone is one of these signals. The approach was to evaluate presence of macrophages immunohistochemically using antibodies to CD68 and CD14. Tissues examined were from cyclic ewes in the luteal phase of the estrous cycle, unilaterally-pregnant ewes at day 140 of pregnancy in which pregnancy was surgically confined to one uterine horn, ovariectomized ewes, and ovariectomized ewes treated with progesterone for 44 days. Macrophages were localized predominately to the stromal compartment of the stratum compactum region of the endometrium. In non-pregnant ewes, macrophages were not abundant regardless of physiological status. Increased numbers of endometrial macrophages were seen for both the pregnant and non-pregnant uterine horns of unilaterally pregnant ewes. Numbers of macrophages were higher in the endometrium from the pregnant uterine horn than from endometrium from the non-pregnant uterine horn. Results indicate that macrophages accumulate in the endometrium by day 140 of pregnancy in the sheep and that this induction is because of both systemic and local signals. Progesterone appears not to be an important regulator of numbers of endometrial macrophages.

Lymphocyte-mediated lysis of sheep chorion: susceptibility of chorionic cells to third-party and maternal cytotoxic lymphocytes and presence of cells in the endometrium exhibiting cytotoxicity toward natural-killer cell targets

In several species, the trophoblast is resistant to lysis by cytotoxic lymphocytes. Such resistance is believed to contribute to survival of the semiallogenic conceptus. We tested whether ovine chorionic cells are susceptible to lysis by specific and nonspecific cytotoxic lymphocytes in peripheral blood (PBL) and whether cytotoxic cells that can lyse target cells for natural-killer cells are present in the endometrium. Primary chorionic cells from pregnant ewes at Days 51–91 of gestation were labeled with 51 Cr and incubated for 20 h at 50:1 and 100:1 ratios with PBL from the pregnant mother or from a third-party ewe. In the absence of interleukin-2 (IL-2), there was no killing of primary chorionic cells by third-party PBL even after infection of chorionic cells with bovine herpes virus-1. Incubation with IL-2-induced cytotoxic action in third-party PBL towards one of six primary chorionic cell preparations only. Primary chorionic cells from two of four placentae were lysed by maternal PBL. Luminal epithelial cells from cyclic ewes and from the pregnant and nonpregnant uterine horns of unilaterally-pregnant ewes were evaluated for the presence of cells capable of killing D17 target cells (a natural-killer cell target). Killing was observed but there was no difference in activity between physiological stages. In contrast, there was intense immunochemical localization of perforin in glandular and luminal endometrial epithelial cells in pregnant ewes, and less intense staining in nonpregnant animals. It is concluded that ovine chorionic cells are generally resistant to killing by natural-killer-like cells and lymphokine-activated killer cells. Generation of maternal cytotoxic lymphocytes against trophoblast can occur in some cases and may contribute to pregnancy loss.

Local versus systemic control of numbers of endometrial T cells during pregnancy in sheep.

Pregnancy in sheep is associated with changes in numbers of specific T-lymphocyte populations in the uterine endometrium. These changes probably contribute to evasion by the conceptus of maternal immunological rejection and indicate a possible role for T cells in placental growth, parturition and post-parturient uterine defence against infection. The purpose of the present experiment was to evaluate the relative importance of systemic signals (i.e. those present throughout the uterus or from the circulation, including conceptus hormones secreted into the maternal blood) versus locally acting conceptus signals for regulating changes in numbers of endometrial lymphocytes during pregnancy. The approach taken was to surgically confine pregnancy to one uterine horn and compare differences in lymphocyte numbers between the two uterine horns as well as between both horns of pregnant ewes with those of ovariectomized ewes. As compared with ovariectomized ewes, there was a decline in numbers of CD45R+ lymphocytes within glandular epithelium and an increase in gammadelta T-cell number within the luminal epithelium. These changes occurred in both the pregnant and non-pregnant uterine horns of unilaterally pregnant ewes. Moreover, there were no significant differences in lymphocyte numbers between the two uterine horns of unilaterally pregnant ewes. Expression of CD25 was absent in tissues from both uterine horns. In conclusion, changes in numbers of endometrial lymphocytes during pregnancy, rather than due to locally acting signals of conceptus origin, are the result of hormonal signals of maternal or conceptus origin that either act directly on endometrial lymphocytes or stimulate the uterine endometrium to induce synthesis of regulatory molecules that affect lymphocyte dynamics.

Pesquisa anatômica sobre a ramificação e a disposição das artérias e veias da placenta de bovinos azebuados

A ramificação e a disposição das artérias e veias placentárias foram estudadas em 20 vacas da raça Nelore. Uma anastomose entre as duas artérias do funículo umbilical aparece em 75% dos casos (70% única e 5% dupla). Os tipos de distribuição i/ásculo-cotiledonário foram baseados nos arranjos das artérias e veias nas suas relações com os cotilédones. Um cotilédone suprido por uma única artéria é drenado por múltiplas veias e, em poucos casos, as artérias e veias suprem e drenam respectivamente cotilédones dos cornos uterinos gestante e não gestante.

Increased expression of cell surface markers on endometrial gamma delta T-cell receptor+ intraepithelial lymphocytes induced by the local presence of the sheep conceptus.

In sheep, gamma delta T-cell receptor (TCR)+ cells are a major lymphocyte subpopulation in the luminal epithelium of the uterine endometrium. During late pregnancy, this population of T cells increases in number and becomes more granulated. This study was performed to determine whether this apparent activation was induced by local effects of the conceptus or systemic effects of pregnancy. The unilaterally-pregnant ewe, in which the conceptus is surgically confined to one uterine horn, was used to distinguish between systemic and local effects of pregnancy on function of endometrial gamma delta TCR+ intraepithelial lymphocytes. Lymphocytes collected from peripheral blood, and from the endometrial luminal epithelium of cyclic and unilaterally-pregnant ewes (day 140 of gestation) were analyzed by flow cytometry. As compared to gamma delta TCR+ lymphocytes in peripheral blood, gamma delta TCR+ intraepithelial lymphocytes from non-pregnant ewes had lower percentage of cells staining positive for CD25, CD44, and L-selectin. There was no effect of pregnancy on the percentage of gamma delta TCR+ peripheral blood lymphocytes staining positive for CD25, CD44, CD29, or L-selectin. Similarly, the percentage of intraepithelial lymphocytes staining positive for these antigens was similar for cells collected from cyclic ewes and cells from the nonpregnant uterine horn of unilaterally-pregnant ewes. In contrast, there was a higher percentage of CD25, CD44, CD29, and L-selectin+ cells for gamma delta TCR+ intraepithelial lymphocytes from the conceptus-containing uterine horn of pregnant ewes than for gamma delta TCR+ intraepithelial lymphocytes from the endometrium of cyclic ewes or from the nonpregnant uterine horn of pregnant ewes. The local presence of the conceptus causes changes in cell surface marker expression on endometrial gamma delta TCR+ intraepithelial lymphocytes during pregnancy. These changes may reflect conceptus-induced activation of this population of cells.

Expulsion of the placenta from the uterus is the principal initiator for collagen degradation in mouse uterus.

In unilaterally pregnant mice, collagen degradation in the non-pregnant uterine horn was not initiated by removal of the fetus only but by removal of both the fetus and placenta. The results indicate that expulsion of the placenta from the uterus is a principal factor in the initiation of the process of collagen degradation simultaneously in the whole uterus.

Ultrasonography of the bovine postpartum uterus with retained fetal membranes.

The aim of this study was to describe the potential application of ultrasound in combination with the rectal palpation method and to compare the results to determine the involution period in 11 Swedish dairy cows with retained fetal membranes (RFM). The animals were examined three times a week during the first 8-week postpartum (PP) period. Significant quantity of abnormal vaginal discharges with concomitant accumulation of snowy fluid and thickening of the endometrial and uterine walls were interpreted as evidence of endometritis. The discharges decreased most markedly during the third week PP concomitantly with a marked decrease in the cervical and uterine size. Resumption of cyclical ovarian activity occurred within a month in 7 animals. Five of these cows had 2 ovulations and two animals had 1 and 3 ovulations, respectively. A slight increase of the cervix and uterine size was observed in all ovulating animals in relation to the oestrous periods. Several different calculation methods of the ultrasonographic results were evaluated to describe the completion of uterine involution and compared with findings at rectal palpation. The best congruency with rectal palpation was found to use a 0.5 cm difference for comparison of the previous pregnant and non-pregnant uterine horns in singleton cows and an 80% reduction of the uterine size in all studied animals.

Is uterine blood flow controlled locally or systemically in the pregnant rabbit?

We tested the hypothesis that uterine blood flow is regulated by systemic circulating factors. The alternative hypothesis is that uterine blood flow is regulated by local factors. Adult female New Zealand White rabbits were subjected to a unilateral tubal ligation and thereafter allowed to become pregnant (n = 9). A group of nonpregnant one-tube-ligated animals served as controls (n = 8). On day 21 of gestation uterine blood flow in the pregnant and nonpregnant uterine horns were measured with 15 microns microspheres. The concentration of prostaglandin E2 metabolites were measured in blood from the uterine veins and from the arterial circulation. Absolute uterine blood flow in the pregnant uterine horn was 12.9 +/- 4.7 versus 5.2 +/- 1.4 ml in the nonpregnant horn (p < 0.05). However, when expressed by blood flow per gram of tissue they were not different (p > 0.1). The uterine blood flow for the nonpregnant uterine horn in the pregnant animals was the same as that of the horns from nonpregnant animals. The level of prostaglandin E metabolites was greater in the uterine vein draining the pregnant horn compared to the nonpregnant horn (p < 0.05). These data support the conclusion that the increase in uterine blood flow observed during pregnancy is controlled largely by local factors induced by pregnancy.

An interferon-induced mx protein: cDNA sequence and high-level expression in the endometrium of pregnant sheep

We have cloned a 2.4-kb cDNA containing the complete coding sequence of ovine mx from a λZAP library constructed using RNA from the endometrium of a normal sheep on day 16 of pregnancy. Ovine mx shows 80% similarity to human MxA. Human and mouse mx are type-1 interferon (IFN)-induced genes that have previously been shown to confer resistance to influenza virus. The ovine mx cDNA contains an open reading frame of 1962 nucleotides (nt) coding for a 653-amino-acid (aa) protein. The deduced translated sequence has consensus GTP-binding sites and similarity to the human MxA sequence (RKFLKERLARL) that has been shown to be essential for resistance against vesicular stomatitis virus (VSV). The presence of mx mRNA was investigated by Northern blot analysis in the endometrium of non-pregnant sheep and between days 8 and 127 of pregnancy. mx expression was detected at high levels between day 13 and day 20 of pregnancy. Furthermore, eightfold higher levels of mx mRNA were detected in the pregnant versus the non-pregnant uterine horn in unilaterally pregnant sheep. mx mRNA can be induced in sheep endometrium by ovine trophoblast interferon (IFN-τ).