Alteration of prostaglandin production and agonist responsiveness by n-6 polyunsaturated fatty acids in endometrial cells from late-gestation ewes

Abstract

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 patternLA<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.

Effect of oleic acid supplementation on prostaglandin production in maternal endometrial and fetal allantochorion cells isolated from late gestation ewes

“…OA also increased PGE2 production in the fetal placenta. Our previous work has similarly demonstrated that supplementation of ME cells isolated from late gestation ewes with LA, conjugated LA, GLA and AA also increased the E:F ratios [28,38]. In contrast to our data, it was demonstrated that LPS induced an endocrine switch from PGF2α to PGE2 in bovine uterine endometrial cells [39].…”

Impact of linoleic acid on bovine oocyte maturation and embryo development

“…This suggests the ability of bovine cumulus cells to metabolize LA and produce PGs. These results are in accordance with a previous study using endometrial cells of late gestation ewes, where the PGE 2 :PGF 2a ratio increased 2-3 times when cells were supplemented with the linoleic, g-linolenic or arachidonic acid (Cheng et al 2004). PGE is an autocrine/ paracrine mediator of oocyte maturation and cumulus expansion.…”

Polyunsaturated fatty acids modulate prostaglandin synthesis by ovine amnion cells in vitro

“…Medium was changed every 48-72 h. At the start of day 6, culture medium was replaced with DMEM/F-12, supplemented with 0.1125% fatty acid-free BSA and 0.1 ml/100 ml ITS media supplement, for a period of 3 h to remove any fatty acids present in the FCS (Cheng et al 2004). Cells were then cultured in the presence of 0, 20 or 100 mM n-6 PUFAs (LA, 18:2, n-6; GLA, 18:3, n-6; DGLA, 20:3, n-6 or AA, 20:4, n-6) or 0, 20 or 100 mM n-3 PUFAs (ALNA, 18:3, n-3; SA, 18:4, n-3; EPA, 20:5, n-3 and DHA, 22:6, n-3) for 45 h, as this time point was shown to be optimal for assessing PG generation following PUFA supplementation in the ovine amnion (Cheng et al 2003).…”