Effects of conjugated linoleic acid on prostaglandins produced by cells isolated from maternal intercotyledonary endometrium, fetal allantochorion and amnion in late pregnant ewes (original) (raw)
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American Journal of Veterinary Research, 2013
Objective-To determine the effects of 2 conjugated linoleic acid (CLA) isomers (cis-9, trans-11 and trans-10, cis-12) on synthesis of prostaglandin (PG) E 2 and F 2α and expression of prostaglandin H synthase-2 (PGHS-2) of adult and fetal bovine endometrial epithelial cells in vitro. Sample-Primary cultures of endometrial epithelial cells obtained from 4 adult cows and 4 fetal bovine carcasses. Procedures-Cells were exposed to 0, 50, 100, or 200µM cis-9, trans-11 or trans-10, cis-12 CLA isomers for 24 hours. Culture media collected before and after 6 hours of stimulation of cells with phorbol 12-myristate 13-acetate were assayed to detect PGE 2 and PGF 2α via ELISA. After stimulation, cells were collected for western blot analysis to quantify PGHS-2. Results-Concentrations of PGF 2α and PGE 2 were significantly lower in culture media of adult and fetal endometrial epithelial cells exposed to any concentration of either CLA than they were in media of cells not exposed to CLAs. The trans-10, cis-12 CLA isomer seemed to decrease PG production more markedly than did the cis-9, trans-11 CLA isomer. Most concentrations of both CLAs significantly reduced culture media PGE 2 :PGF 2α concentration ratios of cells. Exposure of cells to CLAs did not affect expression of PGHS-2 protein.
Journal of Endocrinology, 2004
We investigated the effect of n-6 polyunsaturated fatty acids (PUFAs) on prostaglandin (PG) production by the uterus. A mixed population of endometrial cells (epthelium and stroma) from late-gestation ewes were cultured in defined medium containing linoleic acid (LA, 18:2, n-6), -linolenic acid (GLA, 18:3, or arachidonic acid (AA, 20:4, in concentrations of 0 (control), 20 or 100 µM. After 45 h in test medium with or without added PUFAs, cells were challenged with control medium (CM), oxytocin (OT, 250 nM), lipopolysaccharide (LPS, 0·1 µg/ml) or dexamethasone (DEX, 5 µM) for 22 h in the continued presence of the same concentration of PUFA and the medium was collected for measurement of PGF 2 and PGE 2 . Supplementation with LA inhibited the production of PGF 2 but did not alter PGE 2 , whereas GLA and AA increased production of both PGs. All PUFA supplements thus increased the ratio of PGE 2 to PGF 2 (E:F ratio) two-to threefold. In control cells, OT and LPS challenges stimulated the production of PGF 2 and PGE 2 . In all challenge groups, the concentrations of PGF 2 in response to PUFAs followed the same pattern -LA<control<GLA<AA -but there were significant alterations in responsiveness as a result of PUFA treatment. In the cells supplemented with 100 µM AA, there was no further increase in PGF 2 output in the presence of OT or LPS and when 100 µM GLA was present neither LPS nor OT stimulated PGE 2 significantly. When LPS was given to AA-supplemented cells, the E:F ratio was increased. DEX did not change PGE 2 production in control or LA-treated cells, but the cells produced significantly less PGF 2 , so the E:F ratio was increased. In contrast, in GLA-and AA-treated cells, DEX reduced the production of both PGF 2 and PGE 2 , so the E:F ratio was unaltered. In summary, the study showed altered production of PGs in the presence of different PUFAs according to their position in the n-6 metabolic pathway. The type of PUFA present affected responsiveness to OT, LPS and DEX and also changed the ratio of PGE 2 to PGF 2 produced. The possible implications of this work are discussed in relation to the effect of diet on term and pre-term labour, which both require upregulation of the endometrial PG synthetic pathway.
Journal of Endocrinology, 2005
Polyunsaturated fatty acids derived from the diet are incorporated into cell membranes where they act as precursors for prostaglandin (PG) synthesis. Linoleic acid (LA; 18:2 n-6) is a major constituent of plant oils and its consumption in Westernized populations is increasing. This study investigated the influence of LA on PG production by the uterus and placenta. Pregnant ewes were fed a control or an LA-enriched diet. Oxytocin (OT) was injected on day 45 (early) or day 133 (late) of gestation to measure the release of 13,14-dihydro-15-keto PGF 2 (PGFM). Ewes were killed on day 46 or day 138 for collection of uterine intercaruncular endometrium and fetal allantochorion. Basal and stimulated PG release from explant cultures was assessed before and after in vitro treatment with OT, lipopolysaccharide (LPS), dexamethasone (DEX) or calcium ionophore (CaI). Expression of cyclooxygenase (COX)-1 and COX-2 was determined by Western blot in endometrium of late-gestation ewes. Circulating PGFM levels in vivo did not differ according to diet but there were highly significant differences in the release of PGs in vitro. Basal production of PGF 2 and PGE 2 by the endometrium and of PGE 2 by the allantochorion were all higher in tissues from LA-supplemented ewes. Endometrial tissues produced more PG following OT and CaI treatment, whereas DEX inhibited production of both PGs at both stages of gestation. In allantochorion collected at day 46 LPS did not significantly alter PGE 2 release and DEX increased output, whereas at day 138 LPS was stimulatory but DEX was inhibitory. These data show that a high-LA diet can significantly increase the ability of both endometrium and placental tissues to produce PGs in vitro. This effect of diet may only become apparent after a sustained period of PG release, so was not seen following the brief pulse caused by OT treatment in vivo. As COX protein levels were unaltered, the main influence was likely to be via conversion of LA to arachidonic acid, providing an increased supply of precursor. These results support previous studies which suggest that alterations in dietary polyunsaturated fatty acids may influence the time of labour.
Prostaglandins, Leukotrienes and Essential Fatty Acids, 2001
Long chain n-6 and n-3 fatty acids play important roles in labor and delivery.These effects may be mediated by prostaglandin (PG) synthesis and by regulation of matrix metalloproteinases (MMPs), both of which play roles in uterine contraction, cervical ripening and rupture of fetal membranes.The effects of altering dietary n-6 : n-3 long chain fatty acid ratios, and the addition of dietary conjugated linoleic acids (CLA) and docosahexaenoic acid (DHA) on fatty acid composition of reproductive tissues, PG synthesis in liver and reproductive tissue and serum MMP levels were examined in pregnant rats. Modified AIN-96G diets with n-6 : n-3 ratios of 7:1and 34 :1with and without added1. 1% (by weight) conjugated linoleic acid (CLA) and/or 0.3% (by weight) DHAwere fed through day 20 of gestation. Reproductive tissues readily incorporated both DHA and CLA. CLA significantly (P50.05) depressed PGF 2a synthesis in placenta, uterus and liver by 50% when the n-6 : n-3 ratio was 7:1and by 66% at 34 :1ratio.Significant differences (P50.05) in PGE 2 synthesisin uterus andliver were seen only between groups fed the high ratio of n-6 : n-3 without CLA, and the low ratio with CLA. Addition of CLA to DHA containing diets depressed PGF 2a by onethird in uterus and liver (P50.05). Serum MMP-9 and active MMP-2 were suppressed (P50.05) by addition of either CLA or DHA.
Effects of conjugated linoleic acid (CLA) on hormones and factors involved in urine ovulation
Conjugated linoleic acid is composed of polyunsaturated fatty acids (PUFA) that found in dairy products, beef and lamb. The aim of this study was to determine the effects of different doses of dietary CLA on systemic and local hormones and factors involved in ovulation. In this case-control study, 80 (50±2-day old) female mice were randomly divided into four groups. There were four replicates in each group and there were 5 mice in every replicate (20 mice, in total). The mice in the control group were fed with no CLA in their diet but the ones in the treatment group received 0.1, 0.3 and 0.5g/kg of CLA (replacing corn oil in the diet), respectively for 120 days. Later on, blood samples were obtained from the tails of animals that displayed estrus signs and estradiol, progesterone, LH, FSH, NO, leptin and TNFα were measured. Furthermore, the effects of CLA on the ovarian production of prostaglandins and NO were investigated. The data were analyzed by SAS software. CLA significantly d...
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 2004
Linoleic acid (18:2n-6) is metabolised to arachidonic acid (20:4n-6), the precursor for 2-series prostaglandins (PGs). Increased consumption of 18:2n-6 during pregnancy may thus modify PG synthesis during labour. We have investigated whether increased 18:2n-6 composition during gestation altered the fatty acid consumption and PG synthesis of maternal and fetal tissues in the sheep. Ewes were fed a control diet or a diet providing 40% more 18:2n-6 from 96 days gestation. Half of each group received dexamethasone on day 136 to upregulate the PG synthetic pathways promoting parturition. Maternal and fetal tissues were collected at 138 days. The 18:2n-6 diet significantly increased the 20:4n-6 content of maternal plasma, fetal plasma and allantochorion (51-81%) phosphatidylcholine, and fetal liver (40%) and maternal caruncular endometrium (57%) phosphatidylethanolamine. Increased 18:2n-6 intake increased production of PGF 2a and PGE 2 in all placental tissues (maternal caruncular and intercaruncular endometrium and fetal allantochorion) by 23-98%, whereas dexamethasone increased it by 32-142%. This suggests that consumption of an 18:2n-6-enriched diet in late pregnancy enhanced placental PG production by increasing the supply of 20:4n-6. Variations in the extent to which the diet altered the polyunsaturated fatty acid (PUFA) content of the different tissues indicated complex interactions between nutrient availability and metabolic adaptation. D
Placenta, 2011
Objective: To use an in vitro model of the ovine placenta to determine effects of n-6 polyunsaturated fatty acid (PUFA) supplementation on prostaglandin (PG) production. PGs are key regulators of fetal maturation and parturition. Study design: Fetal allantochorion tissue (FC) was collected in late pregnancy (day 135). FC cells were isolated and cultured with 0e100 mM of linoleic acid (LA), g-linolenic acid (GLA) or arachidonic acid (AA) in serum free medium and challenged with control medium, lipopolysaccharide (LPS, 0.1 mg/ml), dexamethasone (DEX, 5 mM) or a combination of LPS (0.1 mg/ml) with DEX (5 mM). Spent medium was harvested at 2 h and 24 h post challenge for measuring PGs. Main outcome measures: To assess the effects of treatment on placental 1-and 2-series PGE production. Results: LA supplementation inhibited both PGE 1 and PGE 2 production. GLA predominantly stimulated PGE 1 generation, although it also increased PGE 2 production. AA supplementation predominantly increased PGE 2 production, but also stimulated PGE 1 . DEX treatment with or without LPS inhibited PG production. Supplementation with n-6 PUFAs attenuated or neutralised the stimulatory effect of LPS challenge on FC cells for both PGE 1 and PGE 2 production. Conclusion: These data show that supplementation with n-6 PUFAs alters placental PG production, but their precise effects depend on their position in the biosynthetic pathway for PG synthesis. This study supports the possibility that GLA containing oils, widely promoted as dietary supplements, might reduce the risk of pre-term labour by inhibiting the responsiveness of PGE 2 production to LPS challenge in the placenta.
Journal of Dairy Science, 2006
Recent studies have implicated n-3 polyunsaturated fatty acids in the reduction of eicosanoid production in the bovine uterus. The objective of this study was to determine whether the effect of eicosapentaenoic acid (EPA; C 20:5 , n-3) on PGF 2α production by bovine endometrial (BEND) cells is influenced by the quantity of linoleic acid (C 18:2 , n-6) in the incubation medium. Confluent BEND cells were incubated in the absence (control) or presence of 100 M of EPA for 24 h. After incubation, cells were rinsed and then stimulated with phorbol 12,13-dibutyrate (PDBu; 100 ng/mL) for 6 h. Additional sets of culture dishes were treated with a combination of EPA and increasing n-6/n-3 fatty acid ratios for 24 h and then challenged with PDBu for 6 h. The PDBu stimulated PGF 2α secretion and upregulated steadystate concentrations of prostaglandin endoperoxide synthase-2 and peroxisome proliferator-activated receptor delta mRNA within 6 h. Preincubation of BEND cells with EPA for 24 h decreased PGF 2α response to phorbol ester, but had no detectable effects on prostaglandin endoperoxide synthase-2 or peroxisome proliferator-activated receptor delta mRNA abundance in PDBu-stimulated BEND cells. The inhibitory effect of EPA on PGF 2α production was reverted in BEND cells treated with an increasing n-6-ton -3 fatty acid ratio. Findings indicate that the net inhibition of endometrial PGF 2α bioynthesis by n-3 fatty acids may vary depending on the ratio of n-6 to n-3 fatty acids in the uterus.
The Journal of Nutritional Biochemistry, 2006
Shortened gestation is a major cause of infant mortality and morbidity. Evidence from both human and animal studies suggests that essential fatty acids of the n-6 and n-3 series play important and modifiable roles in gestational duration. We examined the influence of linolenic acid (LnA) vs. docosahexaenoic acid (DHA) on rat reproductive tissue prostaglandin (PG) and matrix metalloproteinase (MMP) indices of gestational duration. By varying the oil source of the diet, AIN-93G diets were constructed to provide either 0.7 energy % (en%) LnA, the current US intake of n-3 fatty acids, or 0.7 en% DHA. In addition, enhanced levels of 2.0 en% LnA or 2.0 e% DHA diets were also constructed. All diets contained approximately 6.0 en% linoleic acid (LA), the current US intake of LA. Four groups of 10 female rats were time-mated and fed the respective diets from conception through Day 20 of gestation. Day 20 uterus and placenta DHA were significantly increased by 160-180% by the 0.7 en% DHA diet, and by 250-350% by the 2.0 en% DHA diets in comparison to 0.7 en% LnA diet. DHA diets also significantly reduced uterus and placenta arachidonic acid content. Day 20 placenta and uterus PGE 2 and placenta PGF 2a production rates were significantly reduced by 27-47% in the 0.7 en% DHA group in comparison to 0.7 en% LnA. Increasing LnA to 2.0 en% was without effect. Providing DHA at the enhanced 2.0 en% did not significantly enhance the suppression of PG production. Placenta active MMP-2 and active MMP-9 (gelatinase) production was suppressed significantly by 30 -43% in the 0.7 en% DHA group in comparison to the 0.7 en% LnA group, and 2.0 en% DHA did not enhance this suppression. Placenta collagenase activity comprising the sum of MMP-1, MMP-8 and MMP-13 was also suppressed by 60% in the 0.7 en% DHA diet group with no additional effect with 2.0 en% DHA provision. These results suggest that substituting DHA for LnA even at the current US n-3 fatty acid intake of 0.7 en% is effective in suppressing indices of premature delivery and shortened gestation. Increasing LnA intake by 3-fold to 2.0 en% is not effective. The form of dietary n-3 fatty acid, DHA vs. LnA, appears to be more important than the amount. D
Journal of Dairy Science, 2006
Recent interest in conjugated linoleic acid (CLA) research stems from the well-documented anticarcinogenic, antiatherogenic, antidiabetic, and antiobesity properties of CLA in animal models. The objective of this study was to examine the effects of 2 CLA isomers (cis-9,trans-11 and trans-10,cis-12) on phorbol 12,13dibutyrate (PDBu)-induced PGF 2α production in cultured bovine endometrial (BEND) cells. Confluent BEND cells were incubated in the absence (control) or presence of 100 M each of linoleic acid, cis-9,trans-11 CLA, or trans-10,cis-12 CLA for 24 h. After incubation, cells were rinsed and then stimulated with PDBu (100 ng/mL) for 6 h. Compared with untreated cells, PDBu stimulated PGF 2α secretion (+25-fold) within 6 h. The increases in PGF 2α secretion were paralleled by significant induction of prostaglandin endoperoxide synthase-2 (PGHS-2) mRNA (+63-fold) and protein (+1.6-fold) expression. In spite of stimulatory effects on PGHS-2 and peroxisome proliferator-activated receptor δ (PPARδ) mRNA responses, CLA greatly decreased PGF 2α production by PDBu-stimulated BEND cells. There was no evidence for PDBu or CLA modulation of PPARδ protein synthesis in cultured BEND cells. Results indicated that CLA modulation of PGF 2α production by BEND cells was not mediated through PGHS-2 or PPARδ gene repression.