Biochanin A (BCA) is a multifunctional natural compound that possesses anti-infective, anti-inflammatory, anti-oxidative and hepatoprotective effects. The aim of the study was to assess the therapeutic efficacy of BCA on Schistosoma mansoni-infected mice. Fifty mice were divided into six different groups as non-infected, non-infected BCA-treated, infected untreated, early infected BCA-treated (seven days post-infection (dpi)), late infected BCA-treated 60 dpi and infected praziquantel (PZQ)-treated groups. Parasitological, histopathological examination and immunohistochemical staining of transforming growth factor (TGF)-β, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) were investigated in liver sections. Cytochrome P450 (CYP450) gene expression of S. mansoni was evaluated by quantitative real-time polymerase chain reaction (RT-qPCR). A single dose of BCA significantly reduced worm burden in early (82.14%) and late infection (77.74%), mean tissue egg load in early (7.27 ± 0.495) and late BCA administration (7.63 ± 0.435) and decreased granuloma size. CYP450 mRNA expression was significantly reduced in early BCA treatment as compared to late treatment which emphasizes that early administration of BCA had more pronounced effects on worms than late administration. Both early and late BCA administration led to significant reduction in inflammatory cytokines as TGF and iNOS. Although the reduction of TGF and iNOS in BCA-treated mice was superior to PZQ, no statistically significant differences were noted. However, a significant downregulation of COX2 was noted in hepatocytes as compared to both infected control and PZQ-treated mice. BCA has schistosomicidal, anti-inflammatory, antioxidant and anti-fibrotic effects and could be regarded as a potential drug in schistosomiasis treatment.

Resistant starch (RS) has received increased attention due to its potential health benefits. This study was aimed to investigate the effects of dietary corn RS on immunological characteristics of broilers. A total of 320 broiler chicks were randomly allocated to five dietary treatments: normal corn–soyabean (NC) diet group, corn starch diet group, 4 %, 8 % and 12 % RS diet groups. This trial lasted for 42 d. The relative weights of spleen, thymus and bursa, the concentrations of nitric oxide (NO) and IL-4 in plasma at 21 d of age, as well as the activities of total nitric oxide synthase (TNOS) and inducible nitric oxide synthase (iNOS) in plasma at 21 and 42 d of age showed positive linear responses (P < 0·05) to the increasing dietary RS level. Meanwhile, compared with the birds from the NC group at 21 d of age, birds fed 4 % RS, 8 % RS and 12 % RS diets exhibited higher (P < 0·05) relative weight of bursa and concentrations of NO and interferon-γ in plasma. Birds fed 4 % RS and 8 % RS diets showed higher (P < 0·05) number of IgA-producing cells in the jejunum. While compared with birds from the NC group at 42 d of age, birds fed 12 % RS diet showed higher (P < 0·05) relative weight of spleen and activities of TNOS and iNOS in plasma. These findings suggested that dietary corn RS supplementation can improve immune function in broilers.

Linoleic acid (LA) has a two-sided effect with regard to serum cholesterol-lowering and pro-inflammation, although whether this fatty acid reduces serum cholesterol and the development of atherosclerosis under high-cholesterol conditions has yet to be ascertained. In this study, we examine the effects of dietary LA on reducing serum cholesterol and atherosclerosis development under high-cholesterol conditions. Male and female apoE-deficient (ApoE-/-) mice were fed AIN-76-based diets containing 10% SFA and 0·04 % cholesterol, 10% LA and 0·04% low cholesterol (LALC), or 10% LA and 0·1% high cholesterol (LAHC) for 9 weeks. The results revealed significant reduction in serum cholesterol levels and aortic lesions with increasing levels of pro-inflammatory biomarkers (urinary isoprostane and aortic MCP-1 mRNA) in male and female LALC groups compared with those in the SFA groups (P < 0·05). Furthermore, whereas there were significant increases in the serum cholesterol levels and aortic lesions (P < 0·05), there was no difference in aortic MCP-1 mRNA levels in male and female LAHC groups compared with those in the LALC groups. A high-dietary intake of cholesterol eliminated the serum cholesterol-lowering activity of LA but had no significant effect on aortic inflammation in either male or female ApoE-/- mice. The inhibitory effect of LA on arteriosclerosis is cancelled by a high-cholesterol diet due to a direct increase in serum cholesterol levels. Accordingly, serum cholesterol levels might represent a more prominent pathogenic factor than aortic inflammation in promoting the development of atherosclerosis.

The present study investigated the effects of Porphyra yezoensis enzyme degradation extract (PYEDE) on the brain injuries and neurodegenerative diseases due to oxidative stress. We used in vitro antioxidant systems to verify the antioxidant potential of PYEDE. The results indicated that the PYEDE alleviated weight loss and organ atrophy, reduced the levels of lipid peroxidation and protein carbonylation and elevated reduced glutathione (GSH) content in the serum and brains of the d-galactose-induced ageing model mice. The PYEDE also renewed the glutathione peroxidase (GSH-Px), superoxide dismutase and total antioxidant capability activities, down-regulated the inducible nitric oxide synthase activity and nitric oxide levels, normalised the hippocampal neurons and modulated multiple neurotransmitter systems by inhibiting the activities of acetylcholinesterase and monoamine oxidase in the up-regulation of acetylcholine, dopamine and noradrenaline levels. Overall, the PYEDE is a promising supplement for the alleviation of oxidative stress and age-associated brain diseases.

Monocytes and macrophages are critical effectors and regulators of inflammation and innate immune response, which appear altered in different autoimmune diseases such as systemic lupus erythematosus (SLE). Recent studies suggested that virgin olive oil (VOO) and particularly its phenol compounds might possess preventive effects on different immune-inflammatory diseases, including SLE. Here, we evaluated the effects of VOO (and sunflower oil) on lipopolysaccharide (LPS)-activated peritoneal macrophages from a model of pristane-induced SLE in BALB/c mice, as well as those of the phenol fraction (PF) from VOO on the immune-inflammatory activity and plasticity in monocytes and monocyte-derived macrophages from healthy volunteers. The release of nitrite and inflammatory cytokines was lower in LPS-treated peritoneal macrophages from pristane-SLE mice fed the VOO diet when compared with the sunflower oil diet. PF from VOO similarly decreased the secretion of nitrite and inflammatory cytokines and expression of inducible nitric oxide, PPARγ and Toll-like receptor 4 in LPS-treated human monocytes. PF from VOO also prevented the deregulation of human monocyte subset distribution by LPS and blocked the genetic signature of M1 macrophages while favouring the phenotype of M2 macrophages upon canonical polarisation of naïve human macrophages. For the first time, our study provides several lines of in vivo and in vitro evidence that VOO and PF from VOO target and counteract inflammatory pathways in the monocyte–macrophage lineage of mice with pristane-induced SLE and of healthy subjects, which is a meaningful foundation for further development and application in preclinical and clinical use of PF from VOO in patients with SLE.

Recent studies have strongly indicated the hepatoprotective effect of curcumin; however, the precise mechanisms are not well understood. This study aimed to determine the protective effect of curcumin on hepatic damage and hepatic insulin resistance in biliary duct ligated (BDL) fibrotic rat model. To accomplish this, male Wistar rats were divided into four groups (eight for each): sham group, BDL group, sham+Cur group and BDL+Cur group. The last two groups received curcumin at a dose of 100 mg/kg daily for 4 weeks. The mRNA/protein expression levels of Ras-related C3 botulinum toxin substrate 1 (Rac1), Rac1-GTP, dinucleotide phosphate oxidase 1 (NOX1), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signalling 3 (SOCS3), insulin receptor substrate 1 (IRS1), extracellular signal-regulated kinase 1 (ERK1), specific protein 1 (Sp1) and hypoxia-inducible factor-1α (HIF-1α) were measured by real-time PCR and Western blotting, respectively. Fasting blood glucose, insulin and Leptin levels were determined and homoeostasis model assessment-estimated insulin resistance, as an index of insulin resistance, was calculated. Curcumin significantly attenuated liver injury and fibrosis, including amelioration of liver histological changes, reduction of hepatic enzymes, as well as decreased expression of liver fibrogenesis-associated variables, including Rac1, Rac1-GTP, NOX1, ERK1, HIF-1α and Sp1. Curcumin also attenuated leptin level and insulin resistance, which had increased in BDL rats (P<0·05). Furthermore, compared with the BDL group, we observed an increase in IRS1 and a decrease in SOCS3 and STAT3 expression in the curcumin-treated BDL group (P<0·05), indicating return of these parameters towards normalcy. In conclusion, Curcumin showed hepatoprotective activity against BDL-induced liver injury and hepatic insulin resistance by influencing the expression of some genes/proteins involved in these processes, and the results suggest that it can be used as a therapeutic option.

The intestine plays key roles in maintaining body arginine (Arg) homoeostasis. Meanwhile, the intestine is very susceptible to reactive oxygen species. In light of this, the study aimed to explore the effects of Arg supplementation on intestinal morphology, Arg transporters and metabolism, and the potential protective mechanism of Arg supplementation in piglets under oxidative stress. A total of thirty-six weaned piglets were randomly allocated to six groups with six replicates and fed a base diet (0·95 % Arg,) or base diet supplemented with 0·8 % and 1·6 % l-Arg for 1 week, respectively. Subsequently, a challenge test was conducted by intraperitoneal injection of diquat, an initiator of radical production, or sterile saline. The whole trial lasted 11 d. The diquat challenge significantly decreased plasma Arg concentration at 6 h after injection (P<0·05), lowered villus height in the jejunum and ileum (P<0·05) as well as villus width and crypt depth in the duodenum, jejunum and ileum (P<0·05). Oxidative stress significantly increased cationic amino acid transporter (CAT)-1, CAT-2 and CAT-3, mRNA levels (P<0·05), decreased arginase II (ARGII) and inducible nitric oxide synthase mRNA levels, and increased TNF-α mRNA level in the jejunum (P<0·05). Supplementation with Arg significantly decreased crypt depth (P<0·05), suppressed CAT-1 mRNA expression induced by diquat (P<0·05), increased ARGII and endothelial nitric oxide synthase mRNA levels (P<0·05), and effectively relieved the TNF-α mRNA expression induced by diquat in the jejunum (P<0·05). It is concluded that oxidative stress decreased Arg bioavailability and increased expression of inflammatory cytokines in the jejunum, and that Arg supplementation has beneficial effects in the jejunum through regulation of the metabolism of Arg and suppression of inflammatory cytokine expression in piglets.

Probiotics are known to regulate host immunity by interacting with systemic and mucosal immune cells as well as intestinal epithelial cells. Supplementation with certain probiotics has been reported to be effective against various disorders, including immune-related diseases. However, little is known about the effectiveness of Lactobacillus paracasei GMNL-32 (GMNL-32), Lactobacillus reuteri GMNL-89 (GMNL-89) and L. reuteri GMNL-263 (GMNL-263) in the management of autoimmune diseases, especially systemic lupus erythematosus (SLE). NZB/W F1 mice, which are a lupus-prone animal model, were orally gavaged with GMNL-32, GMNL-89 or GMNL-263 to investigate the effects of these Lactobacillus strains on liver injuries in NZB/W F1 mice. The results thus obtained reveal that supplementary GMNL-32, GMNL-89 or GMNL-263 in NZB/W F1 mice ameliorates hepatic apoptosis and inflammatory indicators, such as matrix metalloproteinase-9 activity and C-reactive protein and inducible nitric oxide synthase expressions. In addition, supplementation with GMNL-32, GMNL-89 or GMNL-263 in NZB/W F1 mice reduced the expressions of hepatic IL-1β, IL-6 and TNF-α proteins by suppressing the mitogen-activated protein kinase and NF-κB signalling pathways. These findings, presented here for the first time, reveal that GMNL-32, GMNL-89 and GMNL-263 mitigate hepatic inflammation and apoptosis in lupus-prone mice and may support an alternative remedy for liver disorders in cases of SLE.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide with universally accepted treatments still lacking. Oral supplementation of sodium butyrate (SoB) has been suggested to attenuate liver damage of various aetiologies. Our study aimed to further delineate mechanisms involved in the SoB-dependent hepatic protection using a mouse model of fructose-induced NAFLD and in in vitro models. C57BL/6J mice were either pair-fed a fructose-enriched liquid diet ±0·6 g/kg body weight per d SoB or standard chow for 6 weeks. Markers of liver damage, intestinal barrier function, glucose metabolism, toll-like receptor-4 (TLR-4) and melatonin signalling were determined in mice. Differentiated human carcinoma colon-2 (Caco-2) and J774A.1 cells were used to determine molecular mechanisms involved in the effects of SoB. Despite having no effects on markers of intestinal barrier function and glucose metabolism or body weight gain, SoB supplementation significantly attenuated fructose-induced hepatic TAG accumulation and inflammation. The protective effects of SoB were associated with significantly lower expression of markers of the TLR-4-dependent signalling cascade, concentrations of inducible nitric oxide synthase (iNOS) protein and 4-hydroxynonenal protein adducts in liver. Treatment with SoB increased melatonin levels and expression of enzymes involved in melatonin synthesis in duodenal tissue and Caco-2 cells. Moreover, treatment with melatonin significantly attenuated lipopolysaccharide-induced expression of iNOS and nitrate levels in J774A.1 cells. Taken together, our results indicated that the protective effects of SoB on the development of fructose-induced NAFLD in mice are associated with an increased duodenal melatonin synthesis and attenuation of iNOS induction in liver.

Overnutrition, insulin resistance and an impaired intestinal barrier function are discussed as critical factors in the development of non-alcoholic fatty liver disease. Not only butyrate-producing probiotics as well as supplementation of sodium butyrate (SoB) have been suggested to bear protective effects on liver damage of various aetiologies. However, whether an oral consumption of SoB has a protective effect on Western-style diet (WSD)-induced non-alcoholic steatohepatitis (NASH) and if so molecular mechanism involved has not yet been determined. Eight-week-old C57BL/6J mice were pair-fed either a liquid control or WSD±0·6 g/kg body weight SoB. After 6 weeks, markers of liver damage, inflammation, toll-like receptor (TLR)-4 signalling, lipid peroxidation and glucose as well as lipid metabolism were determined in the liver tissue. Tight junction protein levels were determined in the duodenal tissue. SoB supplementation had no effects on the body weight gain or liver weight of WSD-fed mice, whereas liver steatosis and hepatic inflammation were significantly decreased (e.g. less inflammatory foci and neutrophils) when compared with mice fed only a WSD. Tight junction protein levels in duodenum, hepatic mRNA expression of TLR-4 and sterol regulatory element-binding protein 1c were altered similarly in both WSD groups when compared with controls, whereas protein levels of myeloid differentiation primary response gene 88, inducible nitric oxide synthase, 4-hydroxynonenal protein adducts and F4/80 macrophages were only significantly induced in livers of mice fed only the WSD. In summary, these data suggest that an oral supplementation of SoB protects mice from inflammation in the liver and thus from the development of WSD-induced NASH.

Chronic inflammatory bowel disease is characterised by an up-regulation of the synthesis and release of a variety of pro-inflammatory mediators leading to excessive tissue injury. Flavonoids are able to inhibit enzymes and/or due to their antioxidant properties regulate the immune response. The goal of the present study was to evaluate the mechanisms of action of phenolic compounds present in grape juice on 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. A total of forty-one male Wistar rats were randomised into seven groups: negative control group; TNBS non-treated induced colitis; 2 % grape juice control group; 1 % grape juice 24 h after TNBS colitis induction; 1 % grape juice on day 7 after colitis induction; 2 % grape juice 24 h after colitis induction; 2 % grape juice on day 7 after colitis induction. The 1 % grape juice-treated induced colitis group showed marked clinical improvement when compared with the TNBS-induced colitis group. Rats that received 1 % grape juice, on day 7 after colitis induction, presented reduced intensity of macroscopic and histological scores. Statistically significant differences (P< 0·05) of TNF-α and inducible NO synthase mRNA expression were detected in the groups treated with grape juice at the 1 % dose after inducing experimental colitis when compared with the TNBS group. Grape juice reduced the noxious effects induced by colitis caused by TNBS, especially at the 1 % dose.

Pharmaco-nutrients have beneficial effects on protective and immunological mechanisms in patients undergoing surgery, which are important for recovery after injury and in combating infectious agents. The aim of this review article was to outline the potential of the administration of nutritional substrates to surgical patients and the underlying mechanisms that make them particularly important in peri-operative care. Surgery causes a stress response, which has catabolic effects on the body's substrate stores. The amino acid glutamine is a stimulating agent for immune cells. It activates protective mechanisms through its role as a precursor for antioxidants and it improves the barrier function of the gut. Arginine also enhances the function of the immune system, since it is the substrate for T-lymphocytes. Furthermore, n-3 PUFA stabilise surgery-induced hyper-inflammation. Taurine is another substrate that may counteract the negative effects of surgical injury on acid–base balance and osmotic balance. These pharmaco-nutrients rapidly become deficient under the influence of surgical stress. Supplementation of these nutrients in surgical patients may restore their protective and immune-enhancing actions and improve clinical outcome. Moreover, pre-operative fasting is still common practice in the Western world, although fasting has a negative effect on the patient's condition and the recovery after surgery. This may be counteracted by a simple intervention such as administering a carbohydrate-rich supplement just before surgery. In conclusion, there are various nutritional substrates that may be of great value in improving the condition of the surgical patient, which may be beneficial for post-operative recovery.

Numerous lines of evidence support a relationship between intestinal inflammation and cancer. Therefore, much attention has recently been focused on the identification of natural compounds with anti-inflammatory activities as a strategy to suppress the early stages of colorectal cancer. Because cocoa is a rich source of bioactive compounds, the present study investigated its anti-inflammatory properties in a rat model of azoxymethane (AOM)-induced colon carcinogenesis and in TNF-α-stimulated Caco-2 cells. A total of forty male rats were fed with control or cocoa-enriched diets (12 %) during 8 weeks and injected with saline or AOM (20 mg/kg body weight) during the third and fourth week (n 10 rats/group). At the end of the experiment, colon samples were evaluated for markers of inflammation. The anti-inflammatory activity of a cocoa polyphenolic extract (10 μg/ml) was examined in TNF-α-stimulated Caco-2 cells, an in vitro model of experimentally induced intestinal inflammation. The signalling pathways involved, including NF-κB and the mitogen-activated protein kinase family such as c-Jun NH2-terminal kinases (JNK), extracellular signal-regulated kinases and p38, were also evaluated. The results show that the cocoa-rich diet decreases the nuclear levels of NF-κB and the expression of pro-inflammatory enzymes such as cyclo-oxygenase-2 and inducible NO synthase induced by AOM in the colon. Additionally, the experiments in Caco-2 cells confirm that cocoa polyphenols effectively down-regulate the levels of inflammatory markers induced by TNF-α by inhibiting NF-κB translocation and JNK phosphorylation. We conclude that cocoa polyphenols suppress inflammation-related colon carcinogenesis and could be promising in the dietary prevention of intestinal inflammation and related cancer development.

α-Lipoic acid (ALA) has been termed the ‘ideal’ antioxidant, a readily absorbed and bioavailable compound capable of scavenging a number of free radicals, and it has been used for treating diseases in which oxidative stress plays a major role. The present study was designed to gain a better understanding for the positive effects of ALA on the models of acute and chronic inflammation in rats, and also determine its anti-oxidative potency. In an acute model, three doses of ALA (50, 100 and 200 mg/kg) and one dose of indomethacin (25 mg/kg) or diclofenac (25 mg/kg) were administered to rats by oral administration. The paw volumes of the animals were calculated plethysmometrically, and 0·1 ml of 1 % carrageenan (CAR) was injected into the hind paw of each animal 1 h after oral drug administration. The change in paw volume was detected as five replicates every 60 min by plethysmometry. In particular, we investigated the activities of catalase, superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), inducible NO synthase (iNOS) and myeloperoxidase (MPx), and the amounts of lipid peroxidation (LPO) or total GSH in the paw tissues of CAR-injected rats. We showed that ALA exhibited anti-inflammatory effects on both acute and chronic inflammations, and a strongly anti-oxidative potency on linoleic acid oxidation. Moreover, the administration of CAR induced oedema in the paws. ALA significantly inhibited the ability of CAR to induce: (1) the degree of acute inflammation, (2) the rise in MPx activity, (3) the increases of GST and iNOS activities and the amount of LPO and (4) the decreases of GPx, GR and SOD activities and the amount of GSH. In conclusion, these results suggest that the anti-inflammatory properties of ALA, which has a strong anti-oxidative potency, could be related to its positive effects on the antioxidant system in a variety of tissues in rats.

The clinical spectrum of Trichomonas vaginalis infection varies from asymptomatic to mild, moderate or severe vaginitis. Nitric oxide and other reactive nitrogen radicals produced by immune effector cells are important cytotoxic and cytostatic mediators against several microorganisms including parasites. In the present study, inducible nitric oxide synthase (iNOS) and reactive nitrogen intermediates (RNI) were determined in leucocyte cultures (stimulated with T. vaginalis in vitro) and vaginal washes (VWs) of 22 symptomatic and 20 asymptomatic T. vaginalis-infected and 20 healthy women by immunoblotting and Griess method respectively. The iNOS protein was detected in leucocytes and VWs of all the symptomatic and asymptomatic women, but was not detected in any of the samples from healthy women. Mean iNOS protein band intensity was significantly higher in leucocytes as compared to VWs (P<0·001) of both symptomatic and asymptomatic women and was also higher in leucocytes of asymptomatic as compared to symptomatic women (P<0·05). Mean RNI concentration was also significantly higher in leucocytes (P<0·01) and VWs (P<0·05) of asymptomatic as compared to symptomatic women, and was also higher in samples of infected as compared to healthy women (P<0·001). These results suggest that reactive nitrogen radicals may have a role in limiting T. vaginalis infection in asymptomatic women.

In this paper, we investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of inducible (i) nitric oxide synthase (iNOS) expression and activity. The signaling pathway involved is also examined. These experiments also provide a link between mAChR activation and the nitric oxide (NO)-dependent regulation of retinal vascular diameter. The diameter of the retinal vessels at a distance of 1 disc diameter from the center of the optic disc was measured in rats using digital retinal photography, and both iNOS-mRNA gene expression and NOS were specifically measured using RT-PCR and [U-14C] citrulline assays, respectively. Stimulation of M1 and M3 mAChR with carbachol caused an increase in vessel diameter, in iNOS-mRNA levels and in NOS activity in the retina. Aminoguanidine, an inhibitor of iNOS, attenuated all these effects. Inhibitors of phospholipase C (PLC) and protein kinase C (PKC) but not calcium/calmodulin (CaM) prevented the muscarinic-dependent increase in iNOS-mRNA levels. The results obtained suggest that the activation of mAChR increases retinal vessel diameters by increasing the production of nitric oxide (NO) through iNOS activation and iNOS-mRNA gene expression. The mechanism appears to occur secondarily to stimulation of PLC and PKC enzymatic activity.

The pattern of expression of a variety of placental nitric oxide synthase isoforms has contributed to elucidating the regulatory mechanisms of nitric oxide (NO) synthesis during gestation. The maintenance of vascular tone, attenuation of vasoconstriction, prevention of platelet and leukocyte adhesion to the trophoblast surface, and possible participation in uterine blood flow seem to be the main functions of NO generated at the fetal-maternal interface in humans and mice. Extending this knowledge to other rodent species commonly used as laboratory animals, in this study we focus on NADPH-diaphorase activity and the distribution of nitric oxide synthase isoforms (NOS) in the trophoblast cells of Calomys callosus during different phases of pregnancy. NADPH-diaphorase activity was evaluated cytochemically and the presence of NOS isoforms detected by immunohistochemistry. These techniques were performed on pre- and postimplantation embryos in situ and in vitro, as well as in placentae on d 14 and 18 of pregnancy. Neither NADPH-diaphorase activity nor inducible or endothelial NOS isoforms were found in pre-implanting embryos except after culturing for at least 48 h, when some of the embryonic cells were positive for the diaphorase reaction. On d 6·5 of pregnancy, trophoblast cells showed intense diaphorase activity both in situ and under in vitro conditions. A positive reaction was also found in the different placental trophoblast cells on d 14 and 18 of pregnancy. The inducible NOS (iNOS) isoform, but not the endothelial isoform, was immunodetected in trophoblast cells from the placenta and from postimplantation embryos in situ and under in vitro conditions. These results strongly suggest the production of NO by the iNOS isoform in the trophoblast of Calomys callosus after embryo implantation. The data also emphasise a possible role for the trophoblast in producing and releasing cytotoxic molecules at the fetal-maternal interface.