Platelet-activating factor-antagonists reduce implantation in mice at low doses only

1995 ◽  
Vol 7 (1) ◽  
pp. 51 ◽  
Author(s):  
C O'Neill
Keyword(s):  
Early Pregnancy ◽  
Embryo Implantation ◽  
Platelet Activating Factor ◽  
Implantation Rate ◽  
Corpora Lutea ◽  
Detailed Knowledge ◽  
Low Doses ◽  
Paf Antagonists ◽  
Implantation Sites ◽  
Web 2086

The effects of a number of platelet-activating factor (PAF)-antagonists on embryo implantation were investigated. Mice were treated from Day 1 to Day 4 of pregnancy with three defined PAF-antagonists: SRI 63 441, BN 52021, and WEB 2086. Necroscopies were performed on Day 8 and the number of implantation sites, the implantation rate (number of implanted embryos compared with the number of corpora lutea) and the proportion of animals pregnant were determined. Each agent caused a reduction in the number of implantation sites at relatively low doses. The dose that had a maximum contragestational effect was 40 micrograms, 10 micrograms and 10 micrograms (per 30 g bodyweight per day) for SRI 63 441, WEB 2086 and BN 52021 respectively. This contragestational effect was completely lost at twice (SRI 63 441), five times (WEB 2086) and ten times (BN 52021) the most effective dose. Treatment with WEB 2086 on the day of implantation (Day 4) by intraperitoneal injection or instillation into the uterus only did not significantly reduce the implantation rate and neither did treatment after implantation (Days 5-8). The results show that the pharmacology of PAF-antagonists in early pregnancy is not simple. An understanding of the actions of these agents in early pregnancy will require a detailed knowledge of their pharmacokinetics, pharmacodynamics and targets of action in early pregnancy.

scholarly journals Arginine enhances embryo implantation in rats through PI3K/PKB/mTOR/NO signaling pathway during early pregnancy

Reproduction ◽  
2013 ◽  
Vol 145 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Xiangfang Zeng ◽  
Xiangbing Mao ◽  
Zhimin Huang ◽  
Fenglai Wang ◽  
Guoyao Wu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Early Pregnancy ◽  
Control Diet ◽  
Embryo Implantation ◽  
Control Group ◽  
Synthesis Inhibitor ◽  
Nitric Oxide Synthase Inhibitor ◽  
No Signaling ◽  
Implantation Sites ◽  
Arginine Supplementation

Our previous study has demonstrated that dietary arginine supplementation during early pregnancy enhanced embryo implantation in rats. However, the mechanism was not clear. The objective of this study was to determine the mechanism that arginine enhanced embryo implantation during early pregnancy. Rats were fed the basal diets supplemented with 1.3% (wt:wt)l-arginine–HCl or 2.2% (wt:wt)l-alanine (isonitrogenous control) once pregnancy. On d4 of pregnancy, rats were given intrauterine injection ofl-NG-nitro arginine methyl ester (l-NAME, nitric oxide synthase inhibitor), α-difluoromethylornithine (DFMO, polyamine synthesis inhibitor), wortmannin (PI3K inhibitor), or rapamycin (mTOR inhibitor). On d7 of pregnancy, rats were killed. Intrauterine injection ofl-NAME decreased the implantation sites, while dietary arginine supplementation increased the implantation sites. Intrauterine injection of DFMO decreased the pregnancy rate, which was reversed by dietary arginine supplementation. Intrauterine injection of rapamycin or wortmannin inhibited embryo implantation. However, dietary arginine supplementation did not reverse this inhibition. Western blot analysis revealed that the expression of uterine p-PKB and p-S6K1 was greater in rats fed the arginine-supplemented diet in the presence ofl-NAME treatment compared with rats fed the control diet. In the presence of DFMO treatment, the expression of uterine iNOS and eNOS was significantly enhanced in the arginine group compared with the control group. Similarly, intrauterine injection of wortmannin or rapamycin decreased the expression of uterine iNOS and eNOS, which was enhanced by dietary arginine supplementation. These data indicated that dietary arginine supplementation during early pregnancy could enhance embryo implantation through stimulation of PI3K/PKB/mTOR/NO signaling pathway.

scholarly journals Endometrial pyruvate kinase M2 is essential for decidualization during early pregnancy

2020 ◽  
Vol 245 (3) ◽  
pp. 357-368 ◽  
Author(s):  
Yan Su ◽  
Sujuan Guo ◽  
Chunyan Liu ◽  
Na Li ◽  
Shuang Zhang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Pyruvate Kinase ◽  
Early Pregnancy ◽  
Stromal Cells ◽  
Embryo Implantation ◽  
Pyruvate Kinase M2 ◽  
Ishikawa Cells ◽  
Implantation Sites

Embryo implantation is essential for normal pregnancy. Decidualization is known to facilitate embryo implantation and maintain pregnancy. Uterine stromal cells undergo transformation into decidual cells after embryo attachment to the endometrium. Pyruvate kinase M2 (PKM2) is a rate limiting enzyme in the glycolysis process which catalyzes phosphoenolpyruvic acid into pyruvate. However, little is known regarding the role of PKM2 during endometrial decidualization. In this study, PKM2 was found to be mainly located in the uterine glandular epithelium and luminal epithelium on day 1 and day 4 of pregnancy and strongly expressed in the decidual zone after embryo implantation. PKM2 was dramatically increased with the onset of decidualization. Upon further exploration, PKM2 was found to be more highly expressed at the implantation sites than at the inter-implantation sites on days 5 to 7 of pregnancy. PKM2 expression was also significantly increased after artificial decidualization both in vivo and in vitro. After PKM2 expression was knocked down by siRNA, the number of embryo implantation sites in mice on day 7 of pregnancy was significantly reduced, and the decidualization markers BMP2 and Hoxa10 were also obviously downregulated in vivo and in vitro. Downregulated PKM2 could also compromise cell proliferation in primary endometrial stromal cells and in Ishikawa cells. The migration rate of Ishikawa cells was also obviously suppressed by si-PKM2 according to the wound healing assay. In conclusion, PKM2 might play an important role in decidualization during early pregnancy, and cell proliferation might be one pathway for PKM2 regulated decidualization.

PAF antagonists inhibit monocrotaline-induced lung injury and pulmonary hypertension

1991 ◽  
Vol 71 (6) ◽  
pp. 2483-2492 ◽  
Author(s):  
S. Ono ◽  
N. F. Voelkel
Keyword(s):  
Pulmonary Hypertension ◽  
Lung Injury ◽  
Right Ventricular ◽  
Ventricular Hypertrophy ◽  
Platelet Activating Factor ◽  
Lipid Mediators ◽  
Right Ventricular Hypertrophy ◽  
Vascular Leak ◽  
Paf Antagonists ◽  
Web 2086

Lung platelet-activating factor (PAF) levels increased in some rats at 1–3 wk after subcutaneous injection of monocrotaline (MCT). We tested the effect of specific PAF antagonists, WEB 2086 and WEB 2170, on MCT-induced lung injury and subsequent pulmonary hypertension and right ventricular hypertrophy. Treatment with either agent decreased MCT-induced pulmonary hypertension and right ventricular hypertrophy at 3 wk after injection. Treatment with WEB 2170 reduced MCT-induced pulmonary vascular leak at 1 wk after injection, and WEB 2086-treatment exclusively during the early leak phase also decreased MCT-induced right ventricular hypertrophy at 3 wk. Treatment with WEB 2170 between the 3rd and 4th wk after MCT injection inhibited the progression of right ventricular hypertrophy at 4 wk. These results suggest that PAF contributes to the early pulmonary vascular leak, and this leak phase is important for the development of pulmonary hypertension and right ventricular hypertrophy in MCT-treated rats. Furthermore, it appears that PAF action contributes to the maintenance of a chronic inflammatory process that involves the synthesis of other lipid mediators (prostaglandins and leukotrienes) and leads to pulmonary hypertension. We conclude that PAF has a role in the MCT-induced inflammatory lung injury and pulmonary hypertension.

scholarly journals 227.An inhibitor of leukemia inhibitory factor signalling blocks embryo implantation in the mouse

2004 ◽  
Vol 16 (9) ◽  
pp. 227
Author(s):  
E. Dimitriadis ◽  
C. Stoikos ◽  
M. Baca ◽  
W. Fairlie ◽  
A. D. Uboldi ◽  
...  
Keyword(s):  
Early Pregnancy ◽  
Leukemia Inhibitory Factor ◽  
Embryo Implantation ◽  
Uterine Horn ◽  
Inhibitory Factor ◽  
Luminal Epithelium ◽  
Pregnant Uterus ◽  
Implantation Sites ◽  
Post Implantation

Embryo implantation is a critical step in the establishment of pregnancy. Endometrial leukemia inhibitory factor (LIF) is essential for embryo implantation in the mouse (1). Uterine LIF is expressed in the luminal epithelium on Day 3 of pregnancy (D3) (D0�=�day of plug detection) and signals via activation of signal transducer and activator of transcription (Stat) 3 (2). We examined the effect of a novel LIF signalling inhibitor on the phosphorylation (p) of Stat3 during early pregnancy and on embryo implantation in the mouse. We injected LIF inhibitor into one uterine horn and PBS into the other uterine horn of the mouse at D3 and examined the effect on pStat3 immunostaining in the luminal epithelium between 30 and 360�min later. We found no immunoreactive pStat3 in luminal epithelium following treatment with LIF inhibitor at 60 and 90�min but variable staining at other time points. The PBS-treated uterine horn showed intense immunostaining at all times. LIF inhibitor (1mg/kg body weight per day) or PBS was administered to mice (a) subcutaneously, (b) intraperitoneally, at 8-hourly intervals for 3�days from D2, or (c) continuously into the peritoneal cavity via Alzet pumps from D2. No effect was seen on implantation at D6. When LIF antagonist (3.5mg/kg/day) or PBS were administered by Alzet pumps from D2 together with ip injections, 4-hourly from D3 for 36�h, there were no implantation sites in the uteri of treated mice (n�=�5) while the control mice (n�=�4) had 3.6���0.5�sites (P�<�0.001). Histologically, the uteri of the treated mice resembled non-pregnant uterus, while the control uterus resembled post-implantation uterus. The results demonstrate that treatment of mice during early pregnancy with a novel LIF inhibitor blocks LIF action in vivo and embryo implantation. This knowledge is important for development of novel contraceptives. (1) Stewart, C. L., Kaspar, P., Brunet, L. J., Bhatt, H., Gadi, I., Kontgen, F., Abbondanzo, S. J. (1992) Nature 359, 76–79. (2) Cheng, J. G., Chen, J. R., Hernandez, L., Alvord, W. G., Stewart, C. L. (2001) Proc. Natl Acad. Sci. USA 98, 8680–8685.

scholarly journals Expression of DNA methyltransferases in the mouse uterus during early pregnancy and susceptibility to dietary folate deficiency

Reproduction ◽  
2012 ◽  
Vol 144 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Y B Ding ◽  
J L He ◽  
X Q Liu ◽  
X M Chen ◽  
C L Long ◽  
...  
Keyword(s):  
Early Pregnancy ◽  
Embryo Implantation ◽  
Dna Methyltransferases ◽  
Deficient Diet ◽  
Mouse Uterus ◽  
Dietary Folate ◽  
Endometrial Cells ◽  
Pregnant Mice ◽  
Implantation Sites ◽  
Significant Expression

We have characterized the uterine expression of DNA methyltransferases (DNMTs) during early pregnancy in mice and determined whether a folate-deficient diet (FDD) can affect DNMTs in this context. Within endometrial cells, expressions of DNMT (cytosine-5) 1 (Dnmt1),Dnmt3a, andDnmt3bwere significantly elevated during the prereceptive phase of pregnancy but generally returned to baseline levels during receptive and postimplantation periods. As such, the transcription of DNMT genes is temporally regulated during early pregnancy. When comparisons were made between implantation sites (IS) and inter-IS on day 5 of pregnancy, lower levels ofDnmt3awere detected at IS. Comparisons between IS and inter-IS did not reveal significant expression differences for other DNMT genes. When tissue sections were examined, DNMT3A was specifically lower in the stroma of IS. Reduced DNMT1 and DNMT3B levels were also observed in the luminal and glandular epithelia of IS, whereas no obvious differences in the stroma were detected. In pseudo-pregnant mice subjected to a FDD, levels ofDnmt1andDnmt3a(but notDnmt3b) were significantly upregulated in endometrial tissues, as compared with controls. When tissues from these folate-deficient mice were examined, DNMT1 levels were elevated in both the luminal and glandular epithelia, whereas DNMT3A was upregulated in the luminal epithelium and the stroma. A slight increase in DNMT3B levels was detected in the glandular epithelium. These results indicate that DNMTs may regulate the transcription of endometrial genes associated with embryo implantation and that levels of DNMTs are affected by dietary folate in mice.

scholarly journals Expression and function of Pdcd4 in mouse endometrium during early pregnancy

Reproduction ◽  
2018 ◽  
Vol 155 (4) ◽  
pp. 393-402 ◽  
Author(s):  
Yue Zhang ◽  
Mingyun Ni ◽  
Na Liu ◽  
Yongjiang Zhou ◽  
Xuemei Chen ◽  
...  
Keyword(s):  
Early Pregnancy ◽  
Quantitative Polymerase Chain Reaction ◽  
Embryo Implantation ◽  
Complex Process ◽  
Programmed Cell Death 4 ◽  
Implantation Sites ◽  
And Function

Embryo implantation is a complex process involving synchronised crosstalk between a receptive endometrium and functional blastocysts. Apoptosis plays an important role in this process as well as in the maintenance of pregnancy. In this study, we analysed the expression pattern of programmed cell death 4 (Pdcd4), a gene associated with apoptosis in the mouse endometrium, during early pregnancy and pseudopregnancy by real-time quantitative polymerase chain reaction, in situ hybridisation, Western blotting and immunohistochemistry. The results showed that Pdcd4 was increased along with days of pregnancy and significantly reduced at implantation sites (IS) from day 5 of pregnancy (D5). The level of Pdcd4 at IS was substantially lower than that at interimplantation sites (IIS) on D6 and D7. In addition, Pdcd4 expression in the endometrium was reduced in response to artificially induced decidualisation in vivo and in vitro. Downregulation of Pdcd4 gene expression in cultured primary stromal cells promoted decidualisation, while upregulation inhibited the decidualisation process by increasing apoptosis. These results demonstrate that Pdcd4 is involved in stromal cell decidualisation by mediating apoptosis and therefore plays a role in embryo implantation in mice.

scholarly journals Testosterone Decreases the Number of Implanting Embryos, Expression of Pinopode and L-selectin Ligand (MECA-79) in the Endometrium of Early Pregnant Rats

2020 ◽  
Vol 17 (7) ◽  
pp. 2293
Author(s):  
Mohd Helmy Mokhtar ◽  
Nelli Giribabu ◽  
Naguib Salleh
Keyword(s):  
Adverse Effect ◽  
Early Pregnancy ◽  
Structural Changes ◽  
Embryo Implantation ◽  
Normal Endometrium ◽  
Pregnant Rats ◽  
Selectin Ligand ◽  
Implantation Sites

Testosterone could have adverse effect on fertility. In this study, we hypothesized that this hormone could reduce the number of embryo implantations via affecting the normal endometrium ultrastructure and expression of endometrial proteins involved in implantation. Therefore, the aims were to identify these adverse testosterone effects. Methods: Intact pregnant rats were given 250 or 500 µg/kg/day testosterone for three days, beginning from day 1 of pregnancy. Rats were euthanized either at day 4 to analyze the ultra-structural changes in the endometrium and expression and distribution of MECA-79 protein, or at day 6 to determine the number of implantation sites. Results: Administration of 500 µg/kg/day testosterone suppresses endometrial pinopodes development and down-regulates expression and distribution of MECA-79 protein in the uterus. In addition, the number of implantation sites were markedly decreased. Conclusions: Changes in endometrial ultrastructure and expression of implantation protein in the endometrium in early pregnancy period could be the reason for failure of embryo implantation under testosterone influence.

Pulmonary vascular reactivity: effect of PAF and PAF antagonists

1992 ◽  
Vol 73 (5) ◽  
pp. 1762-1769 ◽  
Author(s):  
C. R. Chen ◽  
N. F. Voelkel ◽  
S. W. Chang
Keyword(s):  
Angiotensin Ii ◽  
Vascular Reactivity ◽  
Platelet Activating Factor ◽  
Lung Edema ◽  
Physiological Salt Solution ◽  
Similar Response ◽  
Pulmonary Vasodilation ◽  
Pulmonary Vasoconstriction ◽  
Paf Antagonists ◽  
Web 2086

We investigated the effects of two different platelet-activating factor (PAF) antagonists, SRI 63–441 and WEB 2086, on PAF-, angiotensin II-, and hypoxia-induced vasoconstrictions in isolated rat lungs perfused with a physiological salt solution. Bolus injection of PAF (0.5 micrograms) increased pulmonary arterial and microvascular pressures and caused lung edema. Both SRI 63–441, a PAF-analogue antagonist, and WEB 2086, a thienotriazolodiazepine structurally unrelated to PAF, completely blocked PAF-induced vasoconstriction and lung edema at 10(-5) M. At a lower concentration (10(-6) M), WEB 2086 was more effective than SRI 63–441. WEB 2086 also blocked the pulmonary vasodilation induced by low-dose PAF (15 ng) in blood-perfused lungs preconstricted with hypoxia. SRI 63–441 and CV 3988 (another PAF analogue antagonist), but not WEB 2086, caused acute pulmonary vasoconstriction at 10(-5) M and severe lung edema at a higher concentration (10(-4) M). PAF-induced but not SRI- or CV-induced pulmonary vasoconstriction and edema were inhibited by WEB 2086. In addition, SRI 63–441 potentiated angiotensin II- and hypoxia-induced vasoconstrictions. This effect of SRI 63-441 is not due to PAF receptor blockade because 1) addition of PAF (1.6 nM) to the perfusate likewise potentiated angiotensin II-induced vasoconstriction and 2) WEB 2086 did not cause a similar response. We conclude that both SRI 63–441 and WEB 2086 are effective inhibitors of PAF actions in the rat pulmonary circulation. However, antagonists with structures analogous to PAF (SRI 63–441 and CV 3988) can have significant pulmonary vasoactive side effects.

ZUR BEDEUTUNG DES HYPOPHYSÄREN LUTEINISIERUNGSHORMONS FÜR SCHWANGERSCHAFT, GEBURT UND LACTATION BEI DER RATTE

1970 ◽  
Vol 65 (3_Suppl) ◽  
pp. S5-S32 ◽  
Author(s):  
K. Loewit
Keyword(s):  
Luteinizing Hormone ◽  
Early Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
The State ◽  
Termination Of Pregnancy ◽  
Progesterone Level ◽  
Corpora Lutea ◽  
Regulatory Properties ◽  
Duration Of Pregnancy

ABSTRACT The role of luteinizing hormone (LH) for the maintenance of pregnancy, parturition and lactation was investigated by immunological and histochemical methods in the rat. Neutralisation of endogenous rat-LH with Rabbit-Anti-Bovine-LH-Serum (selective hypophysectomy) from days 7-12 of pregnancy resulted in reabsorption of the foetuses and the reappearance of strong 20α-hydroxysteroid-dehydrogenase (20α-OHSD) activity in the corpora lutea (CL) of pregnancy, which normally show no such activity at that time. This effect could be prevented in part by concurrent pregnenolone administration and fully by progesterone, but was not influenced by oestrogen or prolactin. It is concluded that in early pregnancy LH is the main luteotrophic hormone in the rat even though prolactin might act synergistically with it. Antiserum treatment after the 12th day of gestation had no influence on the state or duration of pregnancy or on parturition. LH-injections during the first half of pregnancy had no luteolytic effects i. e. they did not activate 20α-OHSD activity. After day 16 they advanced the reappearance of the enzyme, but delayed parturition or resulted in stillbirths. Neither LH nor antiserum seemed to alter lactation. Since progesterone prevented both the termination of pregnancy and the recurrence of 20α-OHSD activity, it should have some regulatory properties on the enzyme. It is discussed whether the gonadotrophin-dependent progesterone level could regulate the 20α-OHSD activity rather than result from it.

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