Inhibition of nitric oxide production rescues LPS-induced fetal abortion in mice

BCG-trained innate immunity leads to fetal growth restriction by altering immune cell profile in the mouse developing placenta

Trained immunity is a new concept illustrating that innate immune cells are able to undergo a long-term metabolic and epigenetic reprogramming after infection or vaccination, thus displaying either a pro- or an anti-inflammatory phenotype during a sequential unrelated challenge. Innate immune cells such as natural killer (NK) cells and macrophages constitute a large part of the decidual leukocyte population at the maternal-fetal interface, playing an important role in placental development and as such in fetal growth and development. In this study, we hypothesized that training the innate immune cells before pregnancy could have an impact on pregnancy. To test this hypothesis, we used CBA/J x DBA/2 mouse model to investigate pregnancy outcomes and leukocyte population at the maternal-fetal interface. Although we were not able to show a beneficial effect of LPS-tolerogenic training on fetal resorption, Bacillus Calmette-Guérin (BCG) training, known to prime innate immune cells to be proinflammatory, led to fetal growth restriction, without aggravating the fetal resorption rate. We also found that BCG training led to less NK cells and macrophages at the maternal-fetal interface at the early stage of placentation (E9.5), associated with a down-regulation of Ccr3 and Lif mRNA expression. This induced altered leucocyte population profile can be an explanation for the subsequent fetal growth restriction. These data suggest that preconceptional infections-induced trained immunity could influence pregnancy outcomes.

The protective effect of berberine against lipopolysaccharide-induced abortion by modulation of inflammatory/immune responses

OBJECTIVE

Berberine is an isoquinoline derivative alkaloid with anti-inflammatory activity. In this study, we investigated the protective effects of berberine in prevention of LPS-induced abortion.

MATERIALS AND METHODS

On the gestation day (GD) 9.5, the pregnant mice were injected with low, medium, and high doses of berberine or with PBS. After 4 h, berberine or PBS-pretreated mice were injected with LPS. On GD 11.5, blood samples and uterine tissues were collected from treated mice and percentage of abortion and serum levels of NO, TNF-α, IL-10, and IL12p70 were measured by macroscopic examination and sandwich ELISA, respectively.

RESULTS

Our findings show that mice injected with berberine were resistant to LPS-induced abortion. We also found that this treatment prevents the reduction of IL-10 and the enhancement of NO, TNF-α, and IL-12p70 in LPS-treated pregnant mice.

CONCLUSIONS

Taken together, our results suggest that berberine as an anti-inflammatory agent has protective effects on LPS-induced abortion by modulation of inflammatory/immune responses.

Cytokine-induced expression of nitric oxide synthases in Chlamydia trachomatis-infected spontaneous aborters

Purpose: The aim of study was to evaluate expression of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) in Chlamydia trachomatis (CT)-infected spontaneous aborters (SA). Materials and methods: Endometrial curettage tissue was collected from 140 SA (sporadic SA- 70; recurrent SA- 70) (Group I) and 140 age-matched controls (Group II) from Department of Obstetrics and Gynecology, Safdarjung Hospital, New Delhi, India. Polymerase chain reaction was performed for diagnosis of CT. The expression of iNOS/ eNOS/ IFN-γ/ TNF-α was assessed by real-time polymerase chain reaction (PCR). Results: 15.7% SA were CT-positive (Group I); none in controls. Sporadic spontaneous aborters (SSA) (n = 8/70), recurrent spontaneous aborters (RSA) (n = 14/70) diagnosed as CT-positive (Group-I). Significant upregulation of iNOS/ eNOS was found in CT-positive SSA/RSA compared with CT-negative SSA/RSA and healthy controls. TNF-α and IFN-γ were expressed in CT-positive SSA/RSA compared with negative SSA/controls. iNOS showed a significant strong positive correlation with TNF-α and IFN-γ in CT-infected SA. eNOS showed a significant positive correlation with TNF-α and no correlation with IFN-γ in CT-infected SA. TNF-α was positively correlated with IFN-γ. Conclusions: Significantly high expression of iNOS/ eNOS and proinflammatory cytokines affected pregnancy in CT-infected RSA, thereby implying that there occurs cytokine-induced expression of nitric oxide synthase (NOS).

Pathopharmacology of Excessive Hemorrhage in Mifepristone Abortions

Objective:

To explain a pathopharmacologic mechanism that initiates an increase in hemorrhage following medical abortions with mifepristone.

Data Sources:

MEDLINE, PubMed, and Google Scholar databases were searched (1990–July 2007). Key search terms were mifepristone, RU486, medical abortion hemorrhage, bleeding, inflammation, innate immune system, phagocytes, macrocytes, cytokines, interleukins, and nitric oxide.

Study Selection and Data Extraction:

All articles identified from the data sources were evaluated and all information deemed relevant was included for the information related to the development of the understanding of the pathopharmacology of mifepristone as the initiating cause of increased hemorrhage in medical abortions. Mifepristone's blockade of glucocorticoid receptors, prolonged generation of nitric oxide (NO), and postabortion vasodilatation of uterine vasculature by NO that favors excessive hemontiage were the criteria used to determine whether information was relevant for inclusion.

Data Synthesis:

Inescapable bacterial contamination of the decidua accompanies spontaneous, surgical, and mifepristone abortions and is routinely overcome by activation of the innate immune system. The combination of the induction of NO synthase (NOS) and local production of NO is one of the key features of the activation of the innate immune system's phagocytes. NO is a potent vasodilator and is associated with menstrual menorrhagia. Glucocorticoids prevent the overproduction of NOS and NO and thereby contribute to the control of hemorrhage in the postabortion phase.

Conclusions:

Blockade of the glucocorticoid receptors by mifepristone can result in an excess of NO that is theorized to be the cause of excessive hemorrhage seen in mifepristone abortions.

Lipopolysaccharide-induced murine embryonic resorption involves changes in endocannabinoid profiling and alters progesterone secretion and inflammatory response by a CB1-mediated fashion

Genital tract infections are a common complication of human pregnancy that can result in miscarriage. We have previously shown that a lipopolysaccharide (LPS) induces embryonic resorption in a murine model of inflammatory miscarriage. This is accompanied by a dramatic decrease in systemic progesterone levels associated with a robust pro-inflammatory response that results in embryo resorption. Here, we tested the hypothesis that the endogenous cannabinoid system (eCS), through cannabinoid receptor 1 (CB1), plays a role in regulating progesterone levels and, therefore, the pro-inflammatory response. We show that LPS treatment in pregnant mice causes significant changes in the eCS ligands, which are reversed by progesterone treatment. We further show the CB1-KO mice maintain higher plasma progesterone levels after LPS treatment, which is associated with a feebler uterine inflammatory response and a significant drop in embryo resorption. These data suggest that manipulation of CB1 receptors and/or ligands is a potential therapeutic avenue to decrease infection-induced miscarriage.

Effects of Ureaplasma parvum lipoprotein multiple-banded antigen on pregnancy outcome in mice

Ureaplasma spp. are members of the family Mycoplasmataceae and have been considered to be associated with chorioamnionitis and preterm delivery. However, it is unclear whether Ureaplasma spp. have virulence factors related to these manifestations. The purpose of the present study was to determine whether the immunogenic protein multiple-banded antigen (MBA) from Ureaplasma parvum is a virulence factor for preterm delivery. We partially purified MBA from a type strain and clinical isolates of U. parvum, and also synthesized a diacylated lipopeptide derived from U. parvum, UPM-1. Using luciferase assays, both MBA-rich fraction MRF and UPM-1 activated the NF-κB pathway via TLR2. UPM-1 upregulated IL-1β, IL-6, IL-12p35, TNF-α, MIP2, LIX, and iNOS in mouse peritoneal macrophage. MRF or UPM-1 was injected into uteri on day 15 of gestation on pregnant C3H/HeN mice. The intrauterine MRF injection group had a significantly higher incidence of intrauterine fetal death (IUFD; 38.5%) than the control group (14.0%). Interestingly, intrauterine injection of UPM-1 caused preterm deliveries at high concentration (80.0%). In contrast, a low concentration of UPM-1 induced a significantly higher rate of fetal deaths (55.2%) than the control group (14.0%). The placentas of the UPM-1 injection group showed neutrophil infiltration and increased iNOS protein expression. Our data indicate that MBA from the clinical isolate of U. parvum is a potential virulence factor for IUFD and preterm delivery in mice and that the N-terminal diacylated lipopeptide is essential for the initiation of inflammation.

Interleukin-15 is required for maximal lipopolysaccharide-induced abortion

The maternal immune response during pregnancy is critical for the survival of the fetus yet can be detrimental during infection and inflammation. Previously, IL-15 has been observed to mediate inflammation during LPS-induced sepsis. Therefore, we sought to determine whether IL-15 mediates the inflammatory process during LPS-induced abortion through the use of IL-15(-/-) and WT mice. Administration of 2.5 μg LPS i.p. on gd 7.5 drastically reduced fetal viability in WT mice, whereas it had a minimal effect on fetal survival in IL-15(-/-) mice. The uteroplacental sites of LPS-treated WT mice were characterized by vast structural degradation and inflammation compared with treated IL-15(-/-) and untreated controls. This suggests that IL-15 may mediate the inflammation responsible for LPS-induced resorption. As IL-15(-/-) mice are deficient in NK cells and resistant to LPS-induced abortion, these effects suggest that IL-15 may mediate abortion through their homeostatic and/or activation effects on NK cells. WT uteroplacental units exposed to LPS had an increase in the overall number and effector number of NK cells compared with their control counterparts. Furthermore, NK cell depletion before administration of LPS in WT mice partially restored fetal viability. Overall, this paper suggests that IL-15 mediates the inflammatory environment during LPS-induced fetal resorption, primarily through its effects on NK cells.

Spontaneous pregnancy loss mediated by abnormal maternal inflammation in rats is linked to deficient uteroplacental perfusion

Abnormal maternal inflammation during pregnancy is associated with spontaneous pregnancy loss and intrauterine fetal growth restriction. However, the mechanisms responsible for these pregnancy outcomes are not well understood. In this study, we used a rat model to demonstrate that pregnancy loss resulting from aberrant maternal inflammation is closely linked to deficient placental perfusion. Administration of LPS to pregnant Wistar rats on gestational day 14.5, to induce maternal inflammation, caused fetal loss in a dose-dependent manner 3-4 h later, and surviving fetuses were significantly growth restricted. Pregnancy loss was associated with coagulopathy, structural abnormalities in the uteroplacental vasculature, decreased placental blood flow, and placental and fetal hypoxia within 3 h of LPS administration. This impairment in uteroplacental hemodynamics in LPS-treated rats was linked to increased uterine artery resistance and reduced spiral arteriole flow velocity. Pregnancy loss induced by LPS was prevented by maternal administration of the immunoregulatory cytokine IL-10 or by blocking TNF-α activity after treatment with etanercept (Enbrel). These results indicate that alterations in placental perfusion are responsible for fetal morbidities associated with aberrant maternal inflammation and support a rationale for investigating a potential use of immunomodulatory agents in the prevention of spontaneous pregnancy loss.

Tocolytic effect of delta9-tetrahydrocannabinol in mice model of lipopolysaccharide--induced preterm delivery: role of nitric oxide

INTRODUCTION

In this study, we explained that exogenous cannabinoid, Delta(9)-tetrahydrocannabinol (THC), has a preventive effect in a murine model of lipopolysaccharide (LPS)-induced preterm delivery and the contribution of nitric oxide (NO) pathway as a mechanism involved in this process.

STUDY DESIGN

Preterm delivery was induced by double dose of 35 microg/kg LPS with 3-hour interval on gestational day (gd) 15. Delta(9)-tetrahydrocannabinol was administered with (a) double dose (0.02, 0.05, 0.1, 0.5, 1, and 5 mg/kg) 1 hour before each LPS injection, on gd 15 and (b) single administration (0.05, 0.1, and 0.5 mg/kg,) on gds 13 and 14, and the double administration, 1 hour before each LPS injection. To assess the involved mechanism, either AM281 (CB1 receptor antagonist, 2 mg/kg) and AM630 (CB2 receptor antagonist, 5 mg/kg) or N(omega)-nitro-L-arginine methyl ester (L-NAME, 2 mg/kg) was administered 1 hour before each THC injection on gds 13, 14, and 15. The main outcome measurement was the incidence of preterm delivery after injection of last LPS dose. Any interaction in the incidence and time of preterm delivery was ruled out by administration of AM281, AM630, or L-NAME alone.

RESULTS

Chronic THC treatment (0.5 mg/kg) significantly decreased the incidence of LPS-induced premature labor and increased the delivery time. Both AM281 and L-NAME reversed THC-induced attenuation of preterm delivery rate and pregnancy duration. Unlike AM281, AM630 did not influence the rate of preterm delivery in THC-treated mice.

CONCLUSION

Delta(9)-Tetrahydrocannabinol contributes to the regulation of gestational duration in LPS-induced preterm delivery probably by NO coupling through the CB1 receptor.

Soluble tumor necrosis factor receptor mediates cell proliferation on lipopolysaccharide-stimulated cultured human decidual stromal cells

The tumor necrosis factor-alpha (TNF-α) cytokine receptor system modulates apoptosis in many cell types, so we have investigated the role of sTNFR1 in bacterial lipopolysaccharide (LPS)-induced cell death in cultured human decidual stromal cells, hypothesizing that sTNFR1 might play a central role in this action. In this work we characterized in vitro decidual stromal cell viability with LPS treatment and LPS and sTNFR1 co-treatment. We found that LPS treatment induced decidual stromal cell death in a dose-dependent manner and that sTNFR1 blocked the effect of the LPS treatment. There was a significant proliferation among cells co-incubated with LPS at 10 μg/mL and sTNFR1 at 0.1 μg/mL compared with LPS and sTNFR1 at 0.01, 0.05, 0.2 and 0.5 μg/mL (p < 0.01). This study demonstrated that LPS led to decidual stromal cell death in vitro but sTNFR1 down-regulates the cell death due to LPS under the same conditions. Taken together, these results suggested that sTNFR1 could participate in a protective mechanism against endotoxin.

Prenatal exposure to endotoxin in rats attenuates the allergic airways eosinophil infiltration in the adult offspring: role of inducible nitric oxide synthase activation

A correlation between stressful events experienced by the mother during pregnancy and progression of respiratory disease in descendants has been reported. Prenatal exposure to lipopolyssacharide (LPS) reduces allergic airway inflammation in mice offspring. In this study we investigated whether reduction of airways inflammation by maternal LPS exposure involves activation of inducible nitric oxide synthase (iNOS) at prenatal life. Since LPS also induces the release of TNF-alpha, and that this cytokine has been implicated in pathogenesis of asthma, we also evaluated whether TNF-alpha plays a role in the allergic airways inflammation by maternal LPS exposure. Pregnant rats were pretreated with the iNOS inhibitor aminoguanidine (50mg/rat per day; given from day 13 of gestation up to delivery) before exposure to LPS (7mug/kg, given at day 17 of gestation). At adult ages, female and male offspring were sensitized with ovalbumin (OVA), and 14 days later they were challenged with this allergen. OVA challenge in sensitized offspring increased markedly the eosinophil number in bronchoalveolar lavage (BAL) fluid at 48h compared with the non-sensitized group. However, the eosinophil number was largely reduced in offspring from maternal LPS exposure, irrespective of offspring gender. Maternal pretreatment with aminoguanidine fully reversed the eosinophil suppression by LPS. The maternal LPS exposure also reduced the eosinophil number in bone marrow and peripheral blood of offspring, but this was not affected by aminoguanidine. No differences in TNF-alpha levels in BAL fluid were found. In conclusion, our study shows that maternal LPS exposure markedly reduces allergic airways eosinophil recruitment in adult offspring by mechanisms possibly involving iNOS activation.

Nitric oxide mediates prostaglandins' deleterious effect on lipopolysaccharide-triggered murine fetal resorption

Genital tract bacterial infections could induce abortion and are some of the most common complications of pregnancy; however, the mechanisms remain unclear. We investigated the role of prostaglandins (PGs) in the mechanism of bacterial lipopolysaccharide (LPS)-induced pregnancy loss in a mouse model, and we hypothesized that PGs might play a central role in this action. LPS increased PG production in the uterus and decidua from early pregnant mice and stimulated cyclooxygenase (COX)-II mRNA and protein expression in the decidua but not in the uterus. We also observed that COX inhibitors prevented embryonic resorption (ER). To study the possible interaction between nitric oxide (NO) and PGs, we administered aminoguanidine, an inducible NO synthase inhibitor. NO inhibited basal PGE and PGF(2alpha) production in the decidua but activated their uterine synthesis and COX-II mRNA expression under septic conditions. A NO donor (S-nitroso-N-acetylpenicillamine) produced 100% ER and increased PG levels in the uterus and decidua. LPS-stimulated protein nitration was higher in the uterus than in the decidua. Quercetin, a peroxynitrite scavenger, did not reverse LPS-induced ER. Our results suggest that in a model of septic abortion characterized by increased PG levels, NO might nitrate and thus inhibit COX catalytic activity. ER prevention by COX inhibitors adds a possible clinical application to early pregnancy complications due to infections.

Effects of low-dose lipopolysaccharide (LPS) pretreatment on LPS-induced intra-uterine fetal death and preterm labor

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and preterm delivery in rodents. The purpose of the present study was to investigate whether administration of a low-dose LPS to the pregnant mice induce a reduced sensitivity to subsequent high-dose LPS-induced IUFD and preterm labor. We found that LPS-induced IUFD was obviously attenuated when the pregnant mice were pretreated with low-dose LPS (10 microg/kg, i.p.) 24h before high-dose LPS (120 microg/kg, i.p.). Consistent with its protective effect, when administered 24h before high-dose LPS, low-dose LPS pretreatment obviously inhibited the releases of tumor necrosis factor alpha (TNF-alpha) in maternal serum and amniotic fluid and attenuated LPS-induced placental lipid peroxidation and GSH depletion. However, when administered 4h before high-dose LPS, low-dose LPS pretreatment did not induced a reduced sensitivity to subsequent high-dose LPS-induced release of TNF-alpha in maternal serum and amniotic fluid. Actually, low-dose LPS pretreatment 4h before high-dose LPS worsened LPS-induced oxidative stress in mouse placenta and increased nitric oxide production in maternal serum and amniotic fluid. Correspondingly, low-dose LPS pretreatment 4h before high-dose LPS aggravated LPS-induced IUFD. Taken together, these results indicate that whether a low-dose LPS exposure during pregnancy produce LPS hyporesponsiveness depends on the interval between the two doses of LPS. When administered 24h before high-dose LPS, a low-dose LPS pretreatment induces a reduced sensitivity to subsequent high-dose LPS-induced IUFD, TNF-alpha production and oxidative stress.

Reactive oxygen species are involved in lipopolysaccharide-induced intrauterine growth restriction and skeletal development retardation in mice

OBJECTIVE

Maternal infection is a cause of adverse developmental outcomes including embryonic resorption, intrauterine fetal death, and preterm labor. Lipopolysaccharide-induced developmental toxicity at early gestational stages has been well characterized. The purpose of the present study was to investigate the effects of maternal lipopolysaccharide exposure at late gestational stages on intrauterine fetal growth and skeletal development and to assess the potential role of reactive oxygen species in lipopolysaccharide-induced intrauterine fetal growth restriction and skeletal development retardation.

STUDY DESIGN

The timed pregnant CD-1 mice were intraperitoneally injected with lipopolysaccharide (25 to 75 microg/kg per day) on gestational day 15 to 17. To investigate the role of reactive oxygen species on lipopolysaccharide-induced intrauterine fetal growth restriction and skeletal development retardation, the pregnant mice were injected with alpha-phenyl-N-t-butylnitrone (100 mg/kg, intraperitoneally) at 30 minutes before lipopolysaccharide (75 microg/kg per day, intraperitoneally), followed by an additional dose of alpha-phenyl-N-t-butylnitrone (50 mg/kg, intraperitoneally) at 3 hours after lipopolysaccharide. The number of live fetuses, dead fetuses, and resorption sites was counted on gestational day 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated.

RESULTS

Maternal lipopolysaccharide exposure significantly increased fetal mortality, reduced fetal weight and crown-rump and tail lengths of live fetuses, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone in a dose-dependent manner. Alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, almost completely blocked lipopolysaccharide-induced fetal death (63.2% in lipopolysaccharide group versus 6.5% in alpha-phenyl-N-t-butylnitrone + lipopolysaccharide group, P < .01). In addition, alpha-phenyl-N-t-butylnitrone significantly reversed lipopolysaccharide-induced intrauterine growth restriction and skeletal development retardation. However, aminoguanidine, a selective inhibitor of inducible nitric oxide synthase, had little effect. Furthermore, lipopolysaccharide-induced intrauterine fetal death, intrauterine fetal growth restriction, and skeletal development retardation were associated with lipid peroxidation and glutathione depletion in maternal liver, placenta, and fetal liver. Alpha-phenyl-N-t-butylnitrone significantly attenuated lipopolysaccharide-induced lipid peroxidation and glutathione depletion in maternal liver, placenta, and fetal liver.

CONCLUSION

Maternal lipopolysaccharide exposure at late gestational stages results in intrauterine fetal growth restriction and skeletal development retardation in mice. Reactive oxygen species might be, at least in part, involved in lipopolysaccharide-induced intrauterine fetal growth restriction and skeletal development retardation.

Embryotoxicity of the nitric oxide donor sodium nitroprusside in preimplantation bovine embryos in vitro

Many early pregnancy complications are associated with an imbalance in pro- and anti-inflammatory cytokines, resulting in alterations in nitric oxide (NO) profile. Since very little is known about the modus operandi of this free radical in early embryos, this study characterised NO embryotoxicity in terms of bovine embryo development and metabolism. Embryos were generated by in vitro maturation and fertilisation of oocytes aspirated from abattoir-derived ovaries. Zygote to blastocyst rates were measured in SOFaaBSA in the presence and absence of the NO donor sodium nitroprusside (SNP) over the 0-50 microM range (n=10 per group). Since concentrations <10 microM SNP depressed blastocyst rate, blastocyst cell numbers (determined by bisbenzimide staining; n=22 and 20), glucose, pyruvate, lactate (measured ultramicrofluorometrically) and amino acid profiles (quantified by HPLC; n=28 and 23) were assessed at 0 and 10 microM SNP. SNP depressed cell numbers, reduced pyruvate and glucose uptake, perturbed quantitative tyrosine, threonine, phenylalanine, lysine, glycine, tryptophan, methionine and valine profiles, and decreased retention into the negative range (P<0.05). Qualitative asparagine and lysine profiles were affected by SNP, while proportional amino acid production and consumption were increased and decreased, respectively (P<0.05). These findings indicate that SNP (presumably through increases in NO profile): (i) fails to improve bovine embryo development in vitro, (ii) exerts toxic effects, likely through ATP starvation induced by cytochrome c oxidase (oxidative phosphorylation) and glyceraldehyde-3-phosphate dehydrogenase (glycolysis) inhibition, and (iii) may affect albumin endocytosis/hydrolysis or protein biosynthesis, rather than causing a loss of intracellular amino acids or simply depressing their metabolism.

Effects of maternal Campylobacter rectus infection on murine placenta, fetal and neonatal survival, and brain development

BACKGROUND

Maternal periodontal infection has been associated with increased risk of prematurity and low birthweight. Infection and inflammatory pathways that mediate prematurity have also been implicated in neonatal developmental impairments. The objective of this study was to determine whether maternal Campylobacter rectus infection that induces fetal growth restriction in a mouse model also compromises neonatal pup survival, growth, and neurodevelopment.

METHODS

Timed pregnant mice were challenged with C. rectus on gestation day 7.5. One group of animals was sacrificed on embryonic day 16.5 for placental histology and measurement of fetal brain mRNA expression of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. Another group of animals was allowed to deliver to follow pup survival, growth, and brain structure at day 9.

RESULTS

C. rectus challenge resulted in abnormal placental architecture with inflammation and a 2.8-fold increase in fetal brain expression of IFN-gamma (P = 0.04). Pup birthweight was unaffected by C. rectus exposure, but lethality was 3.9-fold higher after 1 week. Ultrastructurally, the 9-day neonatal brain tissue displayed cellular and myelin alterations consistent with white matter damage.

CONCLUSIONS

Maternal C. rectus infection induces placental inflammation and decidual hyperplasia as well as concomitant increase in fetal brain IFN-gamma. Maternal infection increased pup mortality, and preliminary findings demonstrate ultrastructural changes in the hippocampal region of the neonatal brain, in a manner analogous to the effects of maternal infection on white matter damage seen in humans. Thus, the threat of maternal oral infectious exposure during pregnancy may not be limited to the duration of gestation, but may also potentially affect perinatal neurological growth and development.

Murine serum cytokines throughout the estrous cycle, pregnancy and post partum period

Cytokines are pleiotropic glycoproteins participating in many aspects of mammalian reproductive physiology. Although murine models have been established to study normal and pathological pregnancy, the small volume of retrievable sample has hampered investigations into the role of cytokines in these processes. These problems were overcome by using fluid-phase multiplex immunoassays to monitor the serum profiles of 18 cytokines in single animals throughout normal murine reproduction: estrus, diestrus, post coitum, preimplantation, implantation, mid-pregnancy, late pregnancy and post partum. Most cytokines were detectable throughout all stages studied. Modest changes in profile were associated with estrous cyclicity and early pregnancy while virtually all cytokine levels increased markedly in mid- to late pregnancy and either fell slightly or levelled off post partum. The functional interrelationships between the various cytokines and the hormonal milieu are discussed with respect to gestational stage. Although certain profiles supported the 'conventional' Th1:Th2 cytokine paradigm of pregnancy, many of the changes recorded were orchestrated around IL-12 (p40) and (p70). The present findings suggest that the traditional cytokine dichotomy poorly describes complex immunological processes like pregnancy.

Ascorbic acid protects against lipopolysaccharide-induced intra-uterine fetal death and intra-uterine growth retardation in mice

Lipopolysaccharide (LPS) has been associated with adverse developmental outcomes including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and preterm labor. Reactive oxygen species (ROS) mediate LPS-induced developmental toxicity. Ascorbic acid is an antioxidant. In the present study, we investigated the effect of ascorbic acid on LPS-induced IUFD and IUGR in mice. All ICR pregnant mice except controls received an intraperitoneal (75 microg/kg, i.p.) injection of LPS daily on gd 15-17. The experiment was carried out in three different modes. In mode A, the pregnant mice were pretreated with a single dose (500 mg/kg, i.p.) of ascorbic acid before LPS. In mode B, the pregnant mice were administered with a single dose (500 mg/kg, i.p.) of ascorbic acid at 3h after LPS. In mode C, the pregnant mice were administered with 500 mg/kg (i.p.) of ascorbic acid at 30 min before LPS, followed by additional dose (500 mg/kg, i.p.) of ascorbic acid at 3h after LPS. The number of live fetuses, dead fetuses and resorption sites was counted on gd 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. Results showed that maternally administered LPS significantly increased fetal mortality, decreased fetal weight and crown-rump and tail lengths of live fetuses, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone. LPS-induced IUFD and IUGR were associated with lipid peroxidation and GSH depletion in maternal liver, placenta and fetal liver. Pre-treatment with ascorbic acid significantly attenuated LPS-induced lipid peroxidation, decreased fetal mortality, and reversed LPS-induced fetal growth and skeletal development retardation. By contrast to pre-treatment, post-treatment with ascorbic acid had less effect on LPS-induced IUFD, although post-treatment significantly attenuated LPS-induced lipid peroxidation and reversed LPS-induced fetal growth and skeletal development retardation. Furthermore, post-treatment with ascorbic acid reduced the protective effects of pre-treatment on LPS-induced IUFD. All these results suggest that pre-treatment with ascorbic acid protected against LPS-induced fetal death and reversed LPS-induced growth and skeletal development retardation via counteracting LPS-induced oxidative stress, whereas post-treatment had less effect on LPS-induced IUFD.

Melatonin protects against lipopolysaccharide-induced intra-uterine fetal death and growth retardation in mice

Lipopolysaccharide (LPS) has been associated with adverse developmental outcomes, including intra-uterine fetal death (IUFD) and intra-uterine growth retardation (IUGR). However, the exact mechanism for LPS-induced IUFD and IURD remains unclear. LPS stimulates macrophages to generate reactive oxygen species (ROS). Therefore, we hypothesize that ROS may be involved in LPS-induced IUFD and IURD. Melatonin is a powerful endogenous antioxidant. In this study, we investigated the protective effects of melatonin on LPS-induced IUFD and IURD in ICR mice. All pregnant mice except controls received an intraperitoneal (75 microg/kg, i.p.) injection of LPS on gestational day (gd) 15-17. The experiment was carried out in two different modes. In mode A, the pregnant mice received two doses of melatonin within 24 hr, one (5 or 10 mg/kg) injected immediately after LPS and the other (5 or 10 mg/kg) injected at 3 hr after LPS. In mode B, the pregnant mice were pretreated with 10 mg/kg of melatonin 18 hr before LPS and then received two doses of melatonin in 24 hr, one (10 mg/kg) injected immediately after LPS and the other (10 mg/kg) injected 3 hr after LPS. The number of live fetuses, dead fetuses and resorption sites were counted on gd 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. Results showed that post-treatments with melatonin significantly attenuated LPS-induced IUFD in a dose-dependent manner. Surprisingly, pre- plus post-treatments with melatonin almost blocked LPS-induced IUFD. In addition, both post-treatments and pre- plus post-treatments with melatonin significantly alleviated LPS-induced decreases in crown-rump and tail lengths and reversed LPS-induced skeletal developmental retardation. However, melatonin had little effect on LPS-induced decrease in fetal weight. Furthermore, pre- plus post-treatments with melatonin significantly attenuated LPS-induced lipid peroxidation in maternal liver. These results indicate that melatonin protects against LPS-induced IURD and IUGR via counteracting LPS-induced oxidative stress.

Tumor necrosis factor alpha partially contributes to lipopolysaccharide-induced intra-uterine fetal growth restriction and skeletal development retardation in mice

Maternal infection is a cause of adverse developmental outcomes. Lipopolysaccharide (LPS)-induced embryonic resorption, intra-uterine fetal death (IUFD) and preterm labor have been well characterized. In the present study, we investigated the effects of maternal LPS exposure on intra-uterine fetal growth and skeletal development. All pregnant mice except controls received an intraperitoneal injection of LPS (75 microg/kg) on gestational days (GD) 15-17. The number of live fetuses, dead fetuses and resorption sites was counted on GD 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. As expected, perinatal LPS exposure resulted in 63.2% fetal death. LPS significantly lowered fetal weight, reduced crown-rump and tail lengths, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone. Additional experiment showed that a single dose of LPS (75 microg/kg, i.p.) on GD 15 increased the expression of TNF-alpha mRNA in maternal liver and placenta and TNF-alpha concentration in maternal serum and amniotic fluid. Furthermore, pentoxifylline, an inhibitor of TNF-alpha synthesis, significantly inhibited TNF-alpha production, reduced fetal mortality, and reversed LPS-induced fetal intra-uterine growth restriction and skeletal development retardation. Taken together, these results suggest that TNF-alpha is, at least in part, involved in LPS-induced intra-uterine fetal death, intra-uterine growth restriction and skeletal development retardation.

Effect of N-Acetylcysteine on Lipopolysaccharide-Induced Intra-uterine Fetal Death and Intra-uterine Growth Retardation in Mice

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR), and preterm delivery. Reactive oxygen species (ROS) have been associated with LPS-induced developmental toxicity. N-acetylcysteine (NAC) is a glutathione (GSH) precursor and direct antioxidant. The present study investigated the effects of NAC on LPS-induced IUFD and IUGR. All pregnant mice except controls were injected with LPS (75 microg/kg, ip) on gestational day (GD) 15-17. NAC was administered in two different modes. In mode A, the pregnant mice were pretreated with two doses of NAC (either 50 plus 25 mg/kg or 200 plus 100 mg/kg) before LPS, one (either 50 or 200 mg/kg) at 12 h before LPS and the other (either 25 or 100 mg/kg) at 15 min before LPS. In mode B, the pregnant mice were administered with two doses of NAC (either 50 plus 25 mg/kg or 200 plus 100 mg/kg) in 24 h, one (either 50 or 200 mg/kg) injected immediately after LPS and the other (either 25 or 100 mg/kg) injected 3 h after LPS. The number of live fetuses, dead fetuses and resorption sites was counted on GD 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were measured and skeletal development was evaluated. Results showed that pretreatment with NAC significantly alleviated LPS-induced fetal mortality and reversed LPS-induced growth and skeletal development retardation. Correspondingly, pretreatment with NAC significantly attenuated LPS-induced elevation in TNF-alpha concentration in maternal serum and amniotic fluid and lipid peroxidation in maternal and fetal livers. By contrast to pretreatment, posttreatment with NAC had no effect on LPS-induced TNF-alpha production and lipid peroxidation. When administered after LPS, NAC did not protect against LPS-induced IUFD and IUGR and in fact aggravated LPS-induced preterm labor. All these results indicate that NAC had a dual effect on LPS-induced IUFD and IUGR. Pretreatment with NAC improves fetal survival and reverses LPS-induced fetal growth and skeletal development retardation, whereas posttreatment with NAC aggravates LPS-induced preterm labor.

Diesel exhaust affects immunological action in the placentas of mice

We investigated the effect of diesel exhaust (DE) on pregnancy and fetal development in mice at day 14 postcoitum (pc) with a special focus on the placenta. The number of absorbed fetuses increased in groups exposed to DE, and congestion was observed in histological sections of placentas. During placental absorption expression of CYP1A1 mRNA decreased to undetectable levels, whereas expression of TNF alpha mRNA increased approximately twofold over that of the control. Levels of CYP1A1 mRNA in normal placentas from DE-exposed mice were unchanged. mRNA levels of inflammatory cytokines IL-2, IL-5, IL-12 alpha, IL-12 beta, and GM-CSF increased in placentas exposed to DE (0.3 and 3.0 mg diesel exhaust particles (DEP)/m3). Expression of IL-5 mRNA was markedly increased in DE-exposed placentas, although levels were barely detectable in control placentas. IL-6 mRNA expression was increased approximately 10-fold in placentas exposed to DE (3.0 mg DEP/m3). It has been reported that expression of mRNA encoding proteins involved in immune function in the placenta is increased during fetal absorption in mice. In the present study, expression of such mRNA by the placenta was increased by DE exposure. Because it is believed that expression of mRNA in the placenta also affects fetal development, DE may promote fetal absorption. These findings suggest that in mice exposure to DE affects fetal absorption and placental function by modifying expression of immune-related genes during early gestation and expression of endocrine-related genes during late gestation.

Perinatal lipopolysaccharide exposure downregulates pregnane X receptor and Cyp3a11 expression in fetal mouse liver

The pregnane X receptor (PXR) is a member of the nuclear receptor superfamily that regulates cytochrome P450 3A (CYP3A) gene transcription in a ligand-dependent manner. Lipopolysaccharide (LPS)-induced downregulation on PXR and cyp3a11 in adult mouse liver has been well characterized. In this study, we investigated the effects of maternal LPS exposure on PXR and cyp3a11 expression in fetal mouse liver. Pregnant ICR mice were injected intraperitoneally with different doses of LPS (0.1 approximately 0.5 mg/kg) on gestational day (GD) 17. PXR and cyp3a11 mRNA levels were determined using RT-PCR. Erythromycin N-demethylase (ERND) activity was used as an indicator of CYP3A expression in this study. Results showed that LPS significantly downregulated PXR and cyp3a11 mRNA levels and ERND activity in fetal liver in a dose-dependent manner. LPS-induced downregulation of PXR and cyp3a11 mRNA expression and ERND activity was attenuated after pregnant mice were pretreated with alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin trapping agent. Additional experiment revealed that LPS significantly increased lipid peroxidation in fetal liver, which was also attenuated by PBN pretreatment. Furthermore, LPS-induced downregulation of PXR and cyp3a11 mRNA expression and ERND activity was prevented by maternal pretreatment with N-acetylcysteine (NAC). Maternal pretreatment with NAC also inhibited LPS-initiated lipid peroxidation and GSH depletion in fetal liver. However, maternal LPS treatment did not affect nitrite plus nitrate concentration in fetal liver. Correspondingly, aminoguanidine, a selective inhibitor of inducible nitric oxide synthase (iNOS), has no effect on LPS-induced downregulation of PXR and cyp3a11 expression and ERND activity in fetal liver. These results indicated that maternal LPS exposure downregulates PXR and cyp3a11 in fetal mouse liver. Reactive oxygen species (ROS) may be involved in LPS-induced downregulation of PXR and cyp3a11 in fetal mouse liver.

Lipopolysaccharide induces nitric oxide synthase expression and platelet-activating factor increases nitric oxide production in human fetal membranes in culture

BACKGROUND

Platelet-activating factor and nitric oxide may be involved in the initiation of human labour as inflammatory mediators. The aim of this study was to test whether platelet-activating factor and lipopolysaccharide were able to induce nitric oxide synthase expression and stimulate the production of nitric oxide in human fetal membrane explants in culture.

METHODS

Fetal membranes were collected from Caesarean sections at term. RNA was extracted from membranes and subjected to a qualitative RT-PCR to assess the baseline expression of iNOS. Discs of fetal membranes were cultured for 24 hours in the presence of platelet-activating factor at a dose range of 0.1 nanomolar--1 micomolar or 1 microgram/ml lipopolysaccharide. Nitric oxide production was measured via nitrite ions in the culture medium and mRNA for iNOS was detected by RT-PCR.

RESULTS

Culturing the membrane discs in medium containing serum induced nitric oxide synthase expression and platelet-activating factor significantly stimulated the production of nitric oxide under these conditions. When cultured without serum inducible nitric oxide synthase expression was induced by lipopolysaccharide, but not by platelet-activating factor.

CONCLUSION

Platelet-activating factor may have a role in the initiation of labour, at term or preterm, via the increased local production of nitric oxide as an inflammatory mediator. In this model of intrauterine infection, lipopolysaccharide was found to induce iNOS expression by fetal membranes, and this mechanism could be involved in preterm labour.

Systemic and placental productions of tumor necrosis factor contribute to induce fetal mortality in mice acutely infected with Trypanosoma cruzi

Blood levels and placental productions of IFN-gamma and TNF, known to be harmful for pregnancy, were determined in pregnant mice acutely infected with Trypanosoma cruzi and suffering massive fetal losses without congenital infection. INF-gamma was detected mainly at day 9 and TNF at days 17 and 19 of pregnancy in plasma of infected mice. TNF levels were significantly correlated to the percentages of dead fetuses. Placental cells produced TNF but not IFN-gamma, and addition of T. cruzi lysate to such cells strongly stimulated TNF production. Treatment of infected mice with pentoxifylline, known to decrease IFN-gamma production and to inhibit the TNF-alpha gene transcription, reduced the placental production of TNF, and the fetal mortality in comparison to control animals. Altogether these result suggest that TNF produced at systemic and placental levels plays a role in the fetal mortality induced in mice acutely infected with T. cruzi.

Immunology of term and preterm labor

During pregnancy there is an alteration in maternal immunity within the uterus where innate, proinflammatory immune responses are tightly regulated to prevent immunological rejection of the fetal allograft. Disruption of the delicate balance of cytokines by bacteria or other factors increases the production of proinflammatory cytokines at the maternal-fetal interface and activates the parturition mechanism prematurely. Despite years of searching, there is still no broadly effective strategy for preventing preterm labor and most therapies are directed at inhibiting myometrial contractions and improving neonatal outcome. Recent studies with progestins and interleukin-10 (IL-10), however, are showing promise in randomized clinical trials and animal studies. Furthermore, the identification of the Toll-like receptors as upstream mediators of inflammation may offer alternative therapeutic targets for preventing this common pregnancy complication.

Zinc treatment prevents lipopolysaccharide-induced teratogenicity in mice

BACKGROUND

During pregnancy, exposure to lipopolysaccharide (LPS) can lead to abortion, preterm delivery, and teratogenicity. The mechanisms underlying these effects are unclear. Both LPS and ethanol are potent inducers of liver metallothionein (MT), a key Zn binding protein. The teratogenic effects of ethanol have been linked to MT-induced changes in maternal-fetal Zn homeostasis, leading tofetal deficiency. This study was designed to assess whether the teratogenic effects of LPS are also related to MT induction and changes in Zn homeostasis.

METHODS

Non-pregnant normal (MT +/+) and MT-null (MT -/-) mice were injected subcutaneously with 0.5 microg/gm LPS and killed over 48 hr. In MT +/+ mice, liver MT concentrations were elevated from 6 hr, and were maximal at 24 hr (30-fold basal), whereas liver Zn levels were also increased from 6 hr. Plasma Zn concentrations decreased by 80% at 6 hr, and were below normal between 6 and 24 hr. In MT -/- mice, plasma Zn levels were increased from basal between 6 and 16 hr. Dams were injected with LPS, saline, or LPS and ZnSO4 (2 microg/gm, MT +/+ only) on Day 8 of gestation (GDS), killed on GD18, and the fetuses examined for malformations.

RESULTS

External abnormalities were most prevalent in fetuses from MT +/+ dams exposed to LPS, where 34% of fetuses in each litterwere affected. MT +/+ dams treated with LPS and ZnSO4, and MT -/- dams treated with LPS had litters in which 5.4 and 4.8% of fetuses were abnormal respectively.

CONCLUSIONS

The findings of this study strongly support the hypothesis that LPS teratogenicity is mediated at least in part by MT-induced changes in maternal Zn homeostasis,which compromises fetal Zn supply.

Prenatal infection obliterates glutamate-related protection against free hydroxyl radicals in neonatal rat brain

Prenatal infection constitutes an important risk factor for brain injury, in both premature and full-term infants. Unfortunately, as the mechanisms involved are far from understood, no therapeutic strategy emerges to prevent the damage. We tested the hypothesis that administration of lipopolysaccharide (LPS) to gravid female rats enhanced glutamate-induced oxidative stress in brain of pups. A microdialysis probe was implanted into the striatum of 14-day-old animals and the release of hydroxyl radicals (.OH) in the perfusion medium was evaluated. Glutamate promoted a delayed.OH release in the offspring of dams given LPS, contrasting with the.OH decreases observed in control animals. A similar response occurred after infusion of (R,S)-3,5-dihydroxyphenylglycine (DHPG), a Group I metabotropic glutamate receptor (mGluR) agonist. This response was not consecutive to a remote activation of N-methyl-D-aspartate (NMDA) receptors, as it was unaffected by an NMDA receptor antagonist. Furthermore, the response to NMDA itself decreased in the offspring of dams given LPS. Massive amounts of DHPG, however, likely internalizing the mGlu receptor, still blunted the response to NMDA, as in controls. No quantitative variation occurred in mGluR1, mGluR5, or the NR1 subunit of the NMDA receptor between controls and neonates born from LPS-treated dams. Direct LPS injection into age-matched pups, by contrast, affected the response to neither glutamate nor DHPG. These results confirm that normally during perinatal development, the brain is protected from any oxidative stress resulting from excess glutamate, and the results support the hypothesis that maternal infection before delivery may lead to critical brain damage via the release of toxic free radicals.

Anti-abortive effect of Radix scutellariae and Rhizoma atractylodis in mice

The objective of this study is to investigate the significance of natural killer (NK) cells and interleukin-2 in uterus in the early embryo loss (or resorption), and to elucidate the immunological modulation of maternal-fetal interface with Chinese herbal medicine Radix scutellariae (huang qin) and Rhizoma atractylodis (bai zhu). Lipopolysaccharide (LPS) was given via the tail vein to induce abortion in mice at day 7 of gestation. Uterine NK cells and IL-2 contents were analyzed by immunohistochemistry and enzyme linked immunosorbent assay (ELISA), respectively. The number of NK cells was found to be much higher (mean = 180 +/- 39) in the decidua of LPS-treated abortion mice. But when the Chinese herbal medicine was used to prevent LPS-induced abortion, less NK cells (mean = 11 +/- 4) were counted (p < 0.01). The mean value of IL-2 in LPS-treated mice was 5.25 +/- 2.5938 pg/mg protein, higher than (p < 0.05) that of the herb prevention group, which was only 1.86 +/- 0.9789 pg/mg protein. The results therefore indicate that the increase of NK cells in the decidua and IL-2 contents in the uterus in LPS-treated mice is closely related to the embryo loss, and that the Chinese herbal medicine prescription composed of Radix scutellariae and Rhizoma atractylodis has an anti-abortive effect through inhibition of maternal-fetal interface immunity.

Expression of the inducible nitric oxide synthase isoform in chorionic villi in the early spontaneous abortion

To investigate the relationship between inducible nitric oxide synthase (iNOS) and the early spontaneous abortion., in situ hybridization and immunohistochemistry were used to detect the expression of iNOS in trophoblasts in the early pregnancy with and without spontaneous abortion (group I and group II). By light microscopy and computer color magic image analysis system (CMIAS), light density (D) and the positive cell number per statistic square (N/S) in situ hybridization were used to analyze the positive cell index, while total positive cells (N) and the positive unit (Pu) were used in immunohistochemistry. By in situ hybridization, D and N/S in trophoblasts were 0.35 +/- 0.028, 0.07 +/- 0.011 respectively in group I and 0.18 +/- 0.016, 0.015 +/- 0.003 in group II. In terms of immunohistochemical staining, N and Pu were 0.058 +/- 0.007, 11.94 +/- 2.01 in group I and 0.013 +/- 0.009, 1.08 +/- 0.35 in group II in trophoblasts. Significant differences existed between two groups. It is concluded that the higher nitric oxide produced by the higher expression of iNOS in trophoblasts might play an important role in the early spontaneous abortion.