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1.
An attenuated type O foot-and-mouth disease (FMD) virus which was virulent for infant, but not for pregnant, mice proved to be superior to a virulent type C FMD virus in the development of a model system for the study of placental transfer of FMD in mice. When mice were inoculated at day 8 or 12 of gestation with type O FMD virus, the virus was detectable in the maternal pancreas for 3 days and in the placenta for 6 days. Viral levels in the fetus and the amniotic fluid were inconsistent and were apparently due to a spillover from the placental infection. The elimination of the virus from the placenta coincided with the expected production of maternal 7S antibody. Mice inoculated from days 0 to 12 of gestation did not have a significant increase in dead young by day 18 (the day of necropsy). Similarly inoculated mice, when permitted to go to term, produced and raised normal-size litters. Inoculation on day 15 of gestation resulted in an increased number of deaths due to morbidity of the dams. It was concluded that the placenta serves as an active site of infection for FMD virus in pregnant mice, but the fetus is relatively resistant to infection.  相似文献   

2.
The placenta produces several growth factors, including placenta growth factor (PlGF), which are essential for placenta growth and fetal growth. Diabetic pregnancy induces the abnormal placental growth and fetal development. This study investigated whether diabetes in pregnant rats induces changes in PlGF expression in the placenta. Diabetes was induced by a single intravenous injection of streptozotocin (35 mg/kg body weight) on day 0 of pregnancy, blood and tissue samples were collected on day 20 of pregnancy. In the diabetic group, maternal body weight and fetal weight significantly decreased compared to controls. RT-PCR and Western blot analyses showed that expression of PlGF was significantly decreased in placenta by streptozotocin treatment. Immunohistochemical study showed that the positive signal of PlGF in trophoblast cells was decreased in the diabetic group compared to controls. These findings demonstrate the decline of PlGF in the placenta in diabetic pregnancy.  相似文献   

3.
Decreased fertility associated with maternal ageing is a well‐known critical problem, and progesterone (P4) concentration decreases during the menopause transition in women. The corpus luteum (CL) secretes P4, thereby supporting the implantation and maintenance of pregnancy. It is proposed that a bovine model is suitable for studying age‐associated decline of fertility in women because the physiology of cows is similar to that of women and cows have a greater longevity compared with other animal models. Thus, we investigated the age‐dependent qualitative changes and inflammatory responses in the bovine CL. In vivo experiment: Cows were divided into three groups, namely, young (mean age: 34.8 months), middle (80.1 months) and aged (188.9 months). Blood samples were collected on days 7 and 12 during the estrous cycle. In vitro experiments: Cows were divided into young (mean age: 27.6 months) and aged (183.1 months). The CL tissues of these groups were collected from a local slaughterhouse and used for tissue culture experiments. An in vivo experiment, plasma P4 concentration in aged cows was significantly lower than that in young cows, whereas no difference was found regarding the area of CL. An in vitro examination in the bovine CL tissues showed that the luteal P4 concentration, P4 secretion, and mRNA expression of StAR and 3β‐HSD were lower in aged cows compared with young cows, especially in the early luteal phase. However, no differences were detected in the mRNA expression of inflammation‐ and senescence‐related factors and inflammatory responses to lipopolysaccharides between the CL tissues from young and aged cows, indicating that an age‐dependent increase in inflammation is not involved in the luteal function. P4 production and secretion from the bovine CL diminish in old cows, especially during the early luteal phase, suggesting that senescence may affect the luteal function in cows.  相似文献   

4.
Transplacental transmission was demonstrated in pregnant mice subcutaneously inoculated with Getah virus. Viremia was shown in the infected dams, and high-titered virus was detected in the placenta and later in the fetus, suggesting virus invasion of the fetus through hematogenous infection of the placenta. High-titered virus was shown in the fetal brain and muscle and in the brain of the young dying soon after birth. Intrauterine infection resulted in a reduction of the litter size, number of young born alive and survival rate to 1 week of age. These results were further corroborated by necropsy performed several days after virus inoculation. The stage of gestation at the time of virus inoculation greatly influenced these results. Dams inoculated at 12 days of gestation delivered all dead babies, whereas virus inoculation at 5 days of gestation had no effect on the number of young born alive. The dams inoculated at 8 days of gestation had reduced litter sizes and those inoculated at 16 days of gestation produced slightly fewer live babies. Gestational stage at the time of virus inoculation also influenced viral growth in fetuses and placentas. The infection rate was low in dams inoculated at 5 days of gestation, high in dams inoculated at 8 or 16 days of gestation and 100% in dams inoculated at 12 days of gestation. High-titered virus was shown in placentas and fetuses of the dams inoculated at 8, 12 or 16 days of gestation. These results suggest that Getah virus may readily cross the placental barrier through hematogenous infection of the placenta in mice.  相似文献   

5.
Aspects of placental protein and energy metabolism were examined in pregnant ewes subjected to either thermoneutral (TN, 18 to 20 degrees C, 30% humidity, n = 7) or hot (H, 30 to 40 degrees C, 40% humidity, n = 5) temperatures through mid and late gestation. Fetal and placental weights and total content of protein, RNA, and DNA were reduced (P less than .001) in H ewes. Placental protein and RNA concentrations (mg/g) were not different, and DNA concentrations were slightly greater (P less than .1), in H vs TN ewes. Thus, heat seemed to greatly reduce total cell number and placentome size and only slightly decrease cell size. Ratios of RNA to DNA indicated a reduced capacity for protein synthesis in H placenta. However, in vitro fractional rates of protein synthesis in tissue slices from the fetal and maternal placenta and from the myoendometrium were not different between TN and H ewes. The H ewes had greater placental protein concentrations of hydroxyproline and glycine, perhaps suggesting a greater collagen content. In vitro oxygen consumption of fetal placenta, but not of maternal placenta or myoendometrium, was lower in H than in TN ewes. This lower oxygen consumption was partially due to a lower Na+,K+ ATPase-dependent oxygen consumption.  相似文献   

6.
The efficiency of nutrient transport from the pregnant female pig to the developing fetus depends on the size and function of the placenta. It has been reported that maternal and fetal blood vessels are arranged in a cross-countercurrent arrangement within placental microscopic folds. Thus, the blood supplies are in close apposition to each other within these microscopic folds, and maternal and fetal blood flows in approximately opposite directions perpendicular to the plane of the placenta. This arrangement indicates that the width of the microscopic folds influences placental efficiency. The objective of this study was to determine whether differences in pig placental microscopic fold development are associated with differences in fetal size or are influenced by selection for ovulation rate or uterine capacity. Gilts from a randomly selected control line, a line selected for ovulation rate, and a line selected for uterine capacity were slaughtered, and uterine wall samples were collected within the placentas associated with the largest and smallest fetuses in each litter on d 45, 65, 85, and 105 of gestation. The uterine wall samples were processed for histology and analyzed using computer-assisted morphometry. Average width of the placental folds and average width of the placental stroma above the folds were measured. To measure fold complexity, the length of the epithelial bilayer for a given length of placenta was also measured. The width of the folded bilayer increased significantly from d 65 to 105 and was greater in placentas associated with small fetuses compared with large fetuses on d 105 of gestation. In contrast, the width of the placental stroma above the folded bilayer decreased with gestation and decreased more rapidly in placenta associated with the smallest compared with the largest fetus. These results indicate that the width of the microscopic folds of the placental trophoblast/endometrial epithelial bilayer is increased in placenta associated with small fetuses, which we hypothesize will increase the surface area for interaction between maternal and fetal blood supplies, thus improving placental efficiency in response to reduced placental size.  相似文献   

7.
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8.
Sulfate is important for growth and development, and is supplied from mother to fetus throughout pregnancy. We used NaS1 sulfate transporter null (Nas1(-/-)) mice to investigate the role of NaS1 in maintaining sulfate homeostasis during pregnancy and to determine the physiological consequences of maternal hyposulfataemia on fetal, placental and postnatal growth. We show that maternal serum (≤0.5 mM), fetal serum (<0.1 mM) and amniotic fluid (≤0.5 mM) sulfate levels were significantly lower in pregnant Nas1(-/-) mice when compared with maternal serum (?2.0 mM), fetal serum (?1.5 mM) and amniotic fluid (?1.7 mM) sulfate levels in pregnant Nas1(+/+) mice. After 12 days of pregnancy, fetal reabsorptions led to markedly reduced (by ≥50%) fetal numbers in Nas1(-/-) mice. Placental labyrinth and spongiotrophoblast layers were increased (by ?140%) in pregnant Nas1(-/-) mice when compared to pregnant Nas1(+/+) mice. Birth weights of progeny from female Nas1(-/-) mice were increased (by ?7%) when compared to progeny of Nas1(+/+) mice. These findings show that NaS1 is essential to maintain high maternal and fetal sulfate levels, which is important for maintaining pregnancy, placental development and normal birth weight.  相似文献   

9.
Remarkable diversity of size and health of offspring exists after normal pregnancies. When pregnancies are complicated by an extrinsic variable such as inappropriate maternal nutrition, birth weight and health of the neonate are substantially affected. The placenta is the organ through which respiratory gases, nutrients, and wastes are exchanged between the maternal and fetal systems. Thus, transplacental exchange provides for all the metabolic demands of fetal growth. Transplacental exchange is dependent upon uterine and umbilical blood flow, and blood flow rates are in turn dependent in large part upon vascularization of the placenta. Therefore, factors that influence placental vascular development will have a dramatic impact on fetal growth and development, and thereby on neonatal mortality and morbidity. Recent work from our laboratories has focused on the effects of nutrient intake during pregnancy on placental growth and vascular development. Both nutrient restriction of the adult dam and overnourishment of the adolescent dam during pregnancy suppress placental cell proliferation and vascularity. Furthermore, placental expression of angiogenic factors and their receptors, factors that are known to affect vascular growth, are perturbed by level of nutrition. Studies in this area will lead to improved methods to manage nutritionally-compromised pregnancies.  相似文献   

10.
Uteroferrin,also known as type 5 tartrate resistant acid phosphatase ( ACP5 ) or TRAP,is an iron-containing glycoprotein secreted by uterine gland epithelium (GE) in response to progesterone and transported across the placental areoalae into the fetal circulation and allantoic fluid to deliver iron and to stimulate hematopoeisis in pigs.This study determined if ACP5 was expressed in the ovine uterus in response to pregnancy,progesterone,interferon tau,placental lactogen,and placental growth hormone.ACP5 protein was present in uterine GE of cycfic and early pregnant ewes,particularly between days 18 and 120 of pregnancy.ACP5 mRNA was expressed in uterine GE of cyclic and pregnant ewes in the same temporal and cell-specific manner.ACP5 was present in secretions from uterine glands,i.e.,uterine milk,and aUantoic fluid from days 40 to 80 of pregnancy,and in uterine flushings from cyclic and early pregnant ewes.Progesterone induced expression of ACP5 mRNA and intrauterine infusion of recombinant ovine interferon tau further stimulated ACP5 expression in uterine GE of ewes,but intrauterine injections of ovine placental lactogen and ovine growth hormone had no effect on ACP5 expression in uterine GE.These results indicate that ACP5 is:1 ) expressed only in GE in response to progesterone ;2 ) secreted into the uterine lumen and transported into the conceptus via plaeental areolae during pregnancy;and 3) present in secretions from uterine GE and in allantoic fluid.The roles of ACP5 in the ovine uterus may include transport of iron across the placenta and stimulation of hematopoiesis.  相似文献   

11.
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12.
20Alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catalyzes the conversion of progesterone to its inactive form 20alpha-dihydroprogesterone (20alpha-OHP). 20Alpha-HSD is expressed in the murine placenta, suggesting a role, yet unidentified, played by this enzyme during the course of pregnancy. To elucidate the possible roles of 20alpha-HSD during pregnancy, 20alpha-HSD gene expression in the placenta was examined by Northern blot analysis, and progestin (progesterone and 20alpha-OHP) concentrations in the maternal and fetal sera and the amniotic fluid were measured by radioimmunoassay in pregnant Shiba goats. The expression of 20alpha-HSD mRNA was observed in the placenta and the intercaruncular part of the uterus during mid to late pregnancy. Analysis by in situ hybridization revealed that 20alpha-HSD mRNA was mainly localized in the endometrial epithelium of the caruncle side of the placenta. Considerable enzyme activity of 20alpha-HSD was also detected in the cytosolic fraction of the placenta and intercaruncular part of the uterus. Although concentrations of progesterone and 20alpha-OHP in the maternal serum showed similar profiles, progesterone levels in the fetal serum stayed extremely low throughout the pregnancy. The 20alpha-OHP concentration in the fetal serum was always higher than that in the maternal serum. In the amniotic fluid, the concentrations of both progesterone and 20alpha-OHP remained at very low levels throughout the pregnancy. These results support the notion that 20alpha-HSD protects the fetus from the cytotoxic effects of progesterone, and thereby maintains the normal development of the fetus.  相似文献   

13.
Abstract: Background data during the gestation period were obtained from 128 Wistar Hannover GALAS rats and 26 Crl:CD(SD) pregnant rats in the control groups of our previous toxicity studies. The body weights of dams in the Wistar Hannover GALAS rats were significantly lower throughout the gestation period than those in the Crl:CD(SD) rats. In contrast, the time-dependent change in the body weight gain (%) of dams showed very similar trends in both strains. The mean number of live embryos/fetuses in the Wistar Hannover GALAS rats was 12.0, and was lower than that (14.5) in the Crl:CD(SD) rats. The placental weights gradually increased with pregnancy progression and reached a plateau on gestation day (GD) 19, although the embryo/fetal weights rapidly increased from GD 17 to GD 21. The embryo/fetal weights in the Wistar Hannover GALAS rats were significantly lower on only GD 21 than those in the Crl:CD(SD) rats. It is considered that this fetal weight difference between the strains develops during the fetal period, but not during the organogenesis period. In contrast, there were no differences in the placental weights between the two strains. Microscopically, the thickness of the labyrinth zone in the Wistar Hannover GALAS rats was thicker throughout the gestation period than that in the Crl:CD(SD) rats.  相似文献   

14.
In this study, the expression patterns of inhibins, activins, insulin-like growth factor-I (IGF-I) and steroidogenic enzymes in equine placentae recovered during the latter two-thirds of gestation were examined. Concentrations of inhibin A and inhibin pro-alphaC in endometrial and fetal placental tissue homogenates were very low during the period examined, whereas these tissues contained high concentrations of activin A. In both maternal endometrial and fetal placental tissues, activin A levels decreased as pregnancy progressed. Expression of inhibin alpha-subunit was not observed in the placenta using either immunohistochemistry or in situ hybridization. Inhibin/activin betaA-subunit and its mRNA were confined to maternal endometrial glands, whereas immunopositive betaB-subunit was not detected in either endometrial glands or microcotyledons. Cytochrome P450 side chain cleavage enzyme was detected by immunohistochemistry in both endometrial glands and microcotyledons, whereas cytochrome P450 17alpha-hydroxylase/lyase was absent in these tissues. Immunopositive signals for 3beta-hydroxysteroid dehydrogenase and cytochrome P450 aromatase were localized in microcotyledons but not in endometrial glands. Immunohistochemistry revealed that IGF-I was highly expressed in microcotyledons around Day 130, and decreased as pregnancy progressed. Changes in the expression of IGF-I were correlated with the number of PCNA positive cells in the placenta. The present study demonstrated the presence and localized the site of expression of activin, IGF-I and steroidogenic enzymes in equine placental tissues during the latter two-thirds of gestation; the results suggest that activin and IGF-I may be involved in the regulation of placental development.  相似文献   

15.
To study the effect of donor age on oocyte developmental competence and steroid profiles, the crossbred cow (Murray Grey × Brahman) in Yunnan province of China were selected and divided into three groups according to its age. The three groups were young cows (n = 12; 12 months old), middle‐aged cows (n = 15; parity: ≤3 calvings; age: 7–8 years old) and old cows (n = 10; parity: ≥8 calvings; age: ≥15 years old). Cumulus–oocyte complexes (COCs) were collected by 10 consecutive ovum pick up (OPU) sessions with a 4‐day interval between each session, followed by in vitro maturation, fertilization and embryo development. Results showed that cleavage rates (CR) and blastocyst rates (BR) were higher in the young cows than those in the middle‐aged and old cows (p < 0.05). CR and BR from COCs of the first and the fourth OPU sessions were lower than those from other sessions in the young cows and the middle‐aged cows (p < 0.05), whereas the similar phenomenon was not observed in the old cows. Plasma concentrations of oestradiol were higher, and plasma concentrations of progesterone were lower before and during OPU sessions in the young cows compared with those in the same period in the middle‐aged cows or the old cows (p < 0.01). In conclusion, donor age of oocytes could affect developmental competence of oocytes recovered by OPU through the action of steroid hormonal balance on follicle development.  相似文献   

16.
It is well established that especially in prolific ewes the mortality rates are high in lambs with low birth weights and that after birth the absolute growth rates are lower in the surviving light lambs than in the heavier lambs. Differences in the prenatal placental development as the feto-maternal connection could be one of the reasons for this effect. The aim of the present study was to ascertain primary data for the placenta characteristics. Therefore three different genotypes which varied in litter size and weight of all born lambs were studied. In 197 placentas the weight, the number of cotyledones, the diameter of the cotyledones and the weight of ten cotyledones were determined. The total weight of all cotyledones and surface area of the cotyledones (the feto-maternal contact area) were calculated. The effects of the breed, the age of the dams (1.5-7.5 years), the litter size (1-4), the weight of all born lambs (5 classes between 3 and 15 kg) and the ram were tested with the ANOVA/MANOVA procedure (co-variable = weight of the dams before mating). Litter size and weight of all born lambs influenced significantly the morphologicaly parameters of the placenta. In the examined genotypes the placenta weight increased from a minimum of 500 g to 1100 g and the surface of the cotyledones grew from 200 cm2 to 350 cm2 with increasing litter size and increasing weight of all born lambs. This seems to be a maternal compensation mechanism for the raising fetal requirements. With the increase of the litter size the surface area of the cotyledones for each lamb decreases because the possible placental compensation mechanism collapses. This could be a reason for low birth weights and increasing deaths of lambs. A possible influence of the genotype on the characteristics of the placentas is discussed by considering the litter size and the condition of the ewe. Paternal effects were not found.  相似文献   

17.
Correlations between genetic expression in lambs when dams were young (1 yr), middle-aged (2 and 3 yr), or older (older than 3 yr) were estimated with three-trait analyses for weight traits. Weights at birth (BWT) and weaning (WWT) and ADG from birth to weaning were used. Numbers of observations were 7,731, 9,518, 9,512, and 9,201 for Columbia (COLU), Polypay (POLY), Rambouillet (RAMB), and Targhee (TARG) breeds of sheep, respectively. When averaged, relative estimates for WWT and ADG were similar across breeds. Estimates were variable across breeds. On average, direct heritability was greater when environment was young dams (.44 for BWT and .34 for WWT) than when environment was dams of middle age or older (.24 and .28 for BWT and .20 and .16 for WWT, respectively). Maternal heritability was greater when dams were middle-aged or older (.28 and .22 vs .18) for BWT but was greater when dams were younger (.10 vs .05 and .04) for WWT. The estimates of genetic correlations for direct effects across age of dam environments averaged .32 for birth weight and averaged .70 for weaning weight. Average estimates of maternal genetic correlations across age of dam classes were .36 or less for both BWT and WWT. Average estimates of correlations among maternal permanent environmental effects were .49 or less across age of dam classes. Total maternal effects accounted for .33 to .42 of phenotypic variance for BWT and for .09 to .26 of phenotypic variance for WWT. The average estimates of genetic correlations between expressions of the same genotypes with different ages of dams suggest that measurements of BWT of lambs with dams in young, middle, and older age classes should be considered to be separate traits for genetic evaluation and that for WWT measurements with young age of dam class and combined middle and older age of dam classes should be considered to be separate traits for genetic evaluation.  相似文献   

18.
Case report: A 6.5‐year‐old clinically healthy German Shepherd Dog with regular oestrous cycles of 6 months was presented for pregnancy diagnosis on day 38 after ovulation (p.ov.). Ultrasonography revealed three individual placental sites in progressed resorption and two vital adequately developed foetuses sharing a joint placenta. On days 41 and 48 p.ov., sonographic signs indicated normal development of both foetuses, but on day 52 p.ov., both foetuses were found to be dead. A caesarean section was performed the same day. Examination of the removed uterus confirmed the diagnosis of a “twin” pregnancy with two foetuses sharing the same placental site but separate amniotic membranes. One foetus showed generalized oedema (anasarca). Bacterial culture of swabs taken from inside the placental cavity was negative. At histological examination of the uterus, no signs of inflammation were found. Serum relaxin concentrations (day 38, 41, 48 and 52. p.ov.) were consistent with those of bitches with normal pregnancies. Cytogenetic analysis of the two foetuses revealed dizygotic twins, one male and one female according to SRY‐PCR. By genotyping 17 high‐polymorphic canine microsatellites, it could be demonstrated that the two foetuses developed from two different oocytes.  相似文献   

19.
We investigated the morphological effects of testosterone on placental development in a rat model of polycystic ovarian syndrome (PCOS). Testosterone propionate (TP), which was subcutaneously administered to pregnant rats with 5 mg/animal from gestation day (GD) 14 to GD 18, induced a maternal weight reduction without mortality or clinical signs from GD 19 onwards. A decrease in fetal and placental weight, an increase in intrauterine growth retardation (IUGR) rates, and histological changes in the placenta were observed on GD 21 but not on GD15 or 17. Histopathologically, on GD 21, the trophoblast septa thickened, and the maternal sinusoids were narrowed in the labyrinth zone, resulting in a small placenta. Additionally, the placental weight, thickness, and histological morphology in the labyrinth zone on GD 21 in the TP-treated group were nearly identical to those on GD 17 in the control and TP-treated groups. Therefore, it was assumed that the testosterone-induced small placenta was induced in association with the developmental inhibition of the fetal part of the placentas from GD 17 onwards.  相似文献   

20.
Glucose is essential for the development of the fetus. We address here the quantitative expression and immunohistochemical localization of glucose transporter (GLUT1 and GLUT3) in the rabbit placenta during successful pregnancy. Blood glucose level showed a significant decrease at the gestation period in comparison with non-pregnancy. Maternal serum glucose was gradually increased according to fetal development. Quantitative RT-PCR results showed that expression of GLUT1 was significantly increased from day 13 to day 18, while GLUT3 mRNA level was significantly decreased during the same periods. Western blot analysis demonstrated that GLUT1 protein did not change significantly in the placenta during pregnancy when compared to non-pregnant uteri. Immunohistochemistry indicated that distribution of GLUT1 was observed mainly to the surface of the outer trophoblasts, whereas GLUT3 mainly localized to the basal site of the inner trophoblasts and fetal blood vessels. These results suggest that glucose is transported through GLUT1 from the maternal blood stream for use as a placental fuel and for further transport through GLUT3 to the fetal circulation, thus signifying the distinct anatomical localization of GLUT1 and GLUT3 in the rabbit placenta during successful pregnancy.  相似文献   

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