RESUMO
Metabolic alterations in obese and overweight mothers impact the placenta and the fetus, leading to anomalies in fetal growth and lipid accretion. The primary aim of the study was to examine the effect of a saturated fat-rich diet (FD) on growth, lipid accretion, and lipases, leptin and leptin receptor (ObR) expression in the placenta and fetal liver. We also aimed to find a role for fetal leptin in the modulation of placental and fetal liver lipase and ObR expression. Six-week-old rats were fed with a standard rat chow (control) or a 25% FD for 7 weeks until mating and during pregnancy. Also, in a group of control rats, fetuses were injected with leptin on days 19, 20, and 21 of pregnancy. On day 21, we assessed lipidemia, insulinemia, and leptinemia in mothers and fetuses. In the placenta and fetal liver, lipid concentration was assessed by thin layer chromatography (TLC) and the gene expression of lipoprotein lipase (LPL), endothelial lipase, insulin receptor (Insr), leptin, and ObR by RT-PCR. The FD induced hypertriglyceridemia and hyperleptinemia (P<0.01) in mothers and fetuses, an increase in maternal (P<0.05) and fetal weight (P<0.01), overaccumulation of lipids in fetal liver (P<0.01), and enhanced leptin expression in the placenta and fetal liver (P<0.05). Placental expression of IR and LPL was increased (P<0.05), and ObR decreased (P<0.05) in the FD group. Fetal administration of leptin induced the placental and fetal liver downregulation of ObR (P<0.05) and upregulation of LPL expression (P<0.05). The FD led to increased fetal lipid levels, which may result from high maternal lipid availability and fetal leptin effects.
Assuntos
Dieta Hiperlipídica , Ácidos Graxos/farmacologia , Lipídeos/sangue , Lipase Lipoproteica/metabolismo , Placenta/metabolismo , Receptores para Leptina/metabolismo , Animais , Gorduras na Dieta/metabolismo , Gorduras na Dieta/farmacologia , Feminino , Leptina/genética , Leptina/metabolismo , Lipase/genética , Lipase/metabolismo , Lipase Lipoproteica/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Placenta/efeitos dos fármacos , Gravidez , Ratos , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Receptores para Leptina/genéticaRESUMO
Maternal diabetes increases the risk of embryo malformations. Folic acid and safflower oil supplementations have been shown to reduce embryo malformations in experimental models of diabetes. In this study we here tested whether folic acid and safflower oil supplementations interact to prevent embryo malformations in diabetic rats, and analyzed whether they act through the regulation of matrix metalloproteinases (MMPs), their endogenous inhibitors (TIMPs), and nitric oxide (NO) and reactive oxygen species production. Diabetes was induced by streptozotocin administration prior to mating. From Day 0.5 of pregnancy, rats did or did not receive folic acid (15 mg/kg) and/or a 6% safflower oil-supplemented diet. Embryos and decidua were explanted on Day 10.5 of gestation for further analysis of embryo resorptions and malformations, MMP-2 and MMP-9 activities, TIMP-1 and TIMP-2 levels, NO production and lipid peroxidation. Maternal diabetes induced resorptions and malformations that were prevented by folic acid and safflower oil supplementation. MMP-2 and MMP-9 activities were increased in embryos and decidua from diabetic rats and decreased with safflower oil and folic acid supplementations. In diabetic animals, the embryonic and decidual TIMPs were increased mainly with safflower oil supplementation in decidua and with folic acid in embryos. NO overproduction was decreased in decidua from diabetic rats treated with folic acid alone and in combination with safflower oil. These treatments also prevented increases in embryonic and decidual lipid peroxidation. In conclusion, folic acid and safflower oil supplementations interact and protect the embryos from diabetes-induced damage through several pathways related to a decrease in pro-inflammatory mediators.
Assuntos
Diabetes Mellitus Experimental/complicações , Suplementos Nutricionais , Ácido Fólico/uso terapêutico , Gravidez em Diabéticas , Efeitos Tardios da Exposição Pré-Natal/tratamento farmacológico , Substâncias Protetoras/uso terapêutico , Óleo de Cártamo/uso terapêutico , Animais , Anormalidades Congênitas/etiologia , Anormalidades Congênitas/prevenção & controle , Embrião de Mamíferos/efeitos dos fármacos , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/efeitos dos fármacos , Feminino , Reabsorção do Feto/prevenção & controle , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Óxido Nítrico/metabolismo , Gravidez , Resultado da Gravidez , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismoRESUMO
Aberrant arachidonic acid and nitric oxide (NO) metabolic pathways are involved in diabetic embryopathy. Previous works have found diminished concentrations of PGE(2) and PGI(2) in embryos from diabetic rats, and that PGI(2) is capable of increasing embryonic PGE(2) concentrations through the activation of the nuclear receptor PPARdelta. PPARdelta activators are lipid molecules such as oleic and linoleic acids, present in high concentrations in olive and safflower oils, respectively. The aim of this study was to analyze the capability of dietary supplementation with either 6% olive or 6% safflower oils to regulate PGE(2), PGI(2) and NO concentrations in embryos and deciduas from control and diabetic rats during early organogenesis. Diabetes was induced by a single injection of streptozotocin (55 mg/kg) 1 week before mating. Animals were fed with the oil-supplemented diets from Days 0.5 to 10.5 of gestation. PGI(2) and PGE(2) were measured by EIA and NO through the evaluation of its stable metabolites nitrates-nitrites in 10.5 day embryos and deciduas. We found that the olive and safflower oil-supplemented treatments highly reduced resorption and malformation rates in diabetic animals, and that they were able to prevent maternal diabetes-induced alterations in embryonic and decidual PGI(2) and PGE(2) concentrations. Moreover, these dietary treatments prevented NO overproduction in embryos and deciduas from diabetic rats. These data indicate that in maternal diabetes both the embryo and the decidua benefit from the olive and safflower oil supplementation probably through mechanisms that involve the rescue of aberrant prostaglandin and NO generation and that prevent developmental damage during early organogenesis.
Assuntos
Ácido Araquidônico/metabolismo , Gorduras na Dieta/administração & dosagem , Suplementos Nutricionais , Doenças Fetais/prevenção & controle , Óxido Nítrico/metabolismo , Óleos de Plantas/administração & dosagem , Óleo de Cártamo/administração & dosagem , Animais , Diabetes Mellitus Experimental/metabolismo , Dinoprostona/metabolismo , Embrião de Mamíferos/metabolismo , Feminino , Masculino , Modelos Biológicos , Azeite de Oliva , Gravidez , Gravidez em Diabéticas , Ratos , Ratos WistarRESUMO
BACKGROUND: Maternal diabetes is associated with morphological placental abnormalities and foeto-placental impairments. These alterations are linked with a dysregulation of the activity of matrix metalloproteinases (MMPs). We investigated the action of 15deoxyDelta(12,14) prostaglandin J(2) (15dPGJ(2)), a natural ligand of the peroxisome proliferator activated receptor (PPAR) gamma, on MMP-2 and MMP-9 activities and tissue inhibitors of matrix metalloproteinases (TIMP) levels in foetuses and placentas from diabetic rats. MATERIALS AND METHODS: Diabetes was induced in rat neonates by a single streptozotocin administration (90 mg kg(-1) s.c.). At 13.5 days of gestation, foetal and placental homogenates were prepared for the determination of PPARgamma levels (western blot) and 15dPGJ(2) concentration (enzyme-immunoassay), whereas the in vitro effect of 15dPGJ(2) (2 microM) was evaluated on placental and foetal MMPs and TIMP activities (zymography and reverse zymography), nitrate/nitrite concentrations (Griess method) and thiobarbituric acid reactive substances (TBARS). RESULTS: PPARgamma was increased while 15dPGJ(2) was decreased in placentas and foetuses from diabetic rats. 15dPGJ(2) additions were able to reduce the high activities of MMP-2 and MMP-9 present in diabetic placental tissues. 15dPGJ(2) additions reduced MMP-2 activity in control and diabetic foetuses. TIMP-3 levels were decreased in diabetic placentas and 15dPGJ(2) was able to enhance them to control values. Nitrates/nitrites and TBARS, metabolites of MMPs activators, were increased in the diabetic placenta and reduced by 15dPGJ(2). CONCLUSIONS: This study demonstrates that 15dPGJ(2) is a potent modulator of the balance between MMP activities and TIMP levels, which is needed in the correct formation and function of the placenta and foetal organs.
Assuntos
Diabetes Mellitus/metabolismo , Feto/efeitos dos fármacos , Metaloproteinases da Matriz/efeitos dos fármacos , PPAR gama/antagonistas & inibidores , Placenta/efeitos dos fármacos , Prostaglandina D2/análogos & derivados , Animais , Diabetes Mellitus/enzimologia , Modelos Animais de Doenças , Feminino , Feto/metabolismo , Gelatinases/metabolismo , Metaloproteinases da Matriz/metabolismo , Óxido Nítrico/metabolismo , PPAR gama/metabolismo , Placenta/metabolismo , Gravidez , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacologia , Ratos , Ratos Wistar , Inibidores Teciduais de Metaloproteinases/efeitos dos fármacos , Inibidores Teciduais de Metaloproteinases/metabolismoRESUMO
Maternal diabetes impairs fetal development and growth. We studied the effects of maternal diets enriched in unsaturated fatty acids capable of activating peroxisome proliferator-activated receptors (PPARs) on the concentrations of 15deoxyDelta12,14PGJ2 (15dPGJ2), lipid mass, and the de novo lipid synthesis in 13.5-day fetuses from control and diabetic rats. Diabetes was induced by neonatal streptozotocin administration (90 mg/kg). Rats were treated with a standard diet supplemented or not with 6% olive oil or 6% safflower oil from days 0.5 to 13.5 of gestation. Fetuses from diabetic rats fed with the standard diet showed reduced 15dPGJ2 concentrations, whereas maternal treatments with olive and safflower oils increased 15dPGJ2 concentrations. Fetuses from diabetic rats showed increased concentrations of phospholipids and increased synthesis of triglycerides, phospholipids, cholesterol and free fatty acids. Diabetic rat treatments with olive and safflower oils reduced phospholipids, cholesterol, and free fatty acid concentrations and the de novo lipid synthesis in the fetuses. These effects were different from those observed in fetuses from control rats, and seem not to involve PPARgamma activation. In conclusion, olive oil- and safflower oil-supplemented diets provide beneficial effects in maternal diabetes, as they prevent fetal impairments in 15dPGJ2 concentrations, lipid synthesis and lipid accumulation.
Assuntos
Feto/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Receptores Ativados por Proliferador de Peroxissomo/agonistas , Animais , Animais Recém-Nascidos , Colesterol/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/farmacologia , Ácidos Graxos não Esterificados/metabolismo , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Insaturados/farmacologia , Feminino , Feto/metabolismo , Masculino , Azeite de Oliva , Óleos de Plantas/administração & dosagem , Óleos de Plantas/farmacologia , Gravidez , Ratos , Óleo de Cártamo/administração & dosagem , Óleo de Cártamo/farmacologia , Estreptozocina , Triglicerídeos/metabolismoRESUMO
Maternal diabetes promotes an overaccumulation of lipids in the feto-placental unit and impairs feto-placental development and growth. Here, we investigated the role played by the nuclear receptor peroxisome proliferator-activated receptor (PPAR)alpha in lipid metabolism in fetuses and placentas from control and neonatal streptozotocin-induced diabetic rats. Placentas and fetuses were studied on day 13.5 of gestation. The concentrations of PPARalpha (by Western blot) and its endogenous agonist leukotriene B(4) (LTB(4)) (by enzyme immunoassay) were analysed. Placental explants and fetuses were cultured with LTB(4) or clofibrate, and then lipid metabolism analysed (concentrations and synthesis from (14)C-acetate of triglycerides, phospholipids, cholesterol and cholesteryl esters; release of glycerol and free fatty acids (FFAs)). We found that maternal diabetes led to increases in placental concentrations of triglycerides and cholesteryl esters, and fetal concentrations of phospholipids. PPARalpha agonists downregulated fetal and placental lipid concentrations in control and diabetic rats. The synthesis of lipids was reduced in the diabetic placenta but increased in fetuses from diabetic animals. PPARalpha agonists reduced the synthesis of lipids in control placenta and in the fetuses from control and diabetic rats. Glycerol and FFA release was enhanced in the diabetic placenta and in control placenta cultured with PPARalpha agonists. Maternal diabetes led to reductions in fetal and placental LTB(4) concentrations and to increases in placental PPARalpha concentrations. Overall, these data support a novel role of PPARalpha as a regulator of lipid metabolism in the feto-placental unit, relevant in maternal diabetes where fetal and placental PPARalpha, LTB(4) and lipid concentrations are altered.
Assuntos
Diabetes Gestacional/metabolismo , Feto/metabolismo , Metabolismo dos Lipídeos , PPAR alfa/metabolismo , Placenta/metabolismo , Animais , Ácidos Graxos não Esterificados/análise , Feminino , Glicerol/análise , Leucotrieno B4/análise , Leucotrieno B4/metabolismo , Lipídeos/análise , Lipídeos/biossíntese , PPAR alfa/análise , Gravidez , Ratos , Ratos WistarRESUMO
Matrix metalloproteinases (MMPs) play an important role in tissue remodeling that accompanies the rapid growth, differentiation, and structural changes of the placenta and several fetal organs. In the present study, we investigated whether the diabetic maternal environment may alter the regulatory homeostasis exerted by nitric oxide (NO) on MMPs activity in the feto-placental unit from rats at midgestation. We found that NADPH-diaphorase activity, which reflects the distribution and activity of NO synthases (NOS), was increased in both placenta and fetuses from diabetic rats when compared with controls. In addition, while a NO donor enhanced MMP2 and MMP9 activities, a NOS inhibitor reduced these activities in the maternal side of the placenta from control rats. This regulatory effect of NO was only observed on MMP9 in the diabetic group. On the other hand, the NO donor did not modify MMP2 and MMP9 activities, while the NOS inhibitor reduced MMP9 activity in the fetal side of both control and diabetic placentas. In the fetuses, MMP2 was enhanced by the NO donor and reduced by the NO inhibitor in both fetuses from control and diabetic rats. Overall, this study demonstrates that NO is able to modulate the activation of MMPs in the feto-placental unit, and provides supportive evidence that increased NOS activity leads to NO overproduction in the feto-placental unit from diabetic rats, an alteration closely related to the observed MMPs dysregulation that may have profound implications in the formation and function of the placenta and the fetal organs.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Feto/enzimologia , Metaloproteinases da Matriz/metabolismo , Óxido Nítrico/fisiologia , Placenta/enzimologia , Animais , Western Blotting/métodos , Eletroforese em Gel de Poliacrilamida , Feminino , Feto/efeitos dos fármacos , Metaloproteinase 2 da Matriz/análise , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/análise , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinases da Matriz/análise , NG-Nitroarginina Metil Éster/farmacologia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/análise , Óxido Nítrico Sintase Tipo III/análise , Nitroprussiato/farmacologia , Placenta/efeitos dos fármacos , Gravidez , Ratos , Ratos WistarRESUMO
Maternal diabetes significantly increases the risk of congenital malformations, and the mechanisms involved are not yet clarified. This study was designed to address peroxisome proliferator-activated receptor delta (PPARdelta) involvement in diabetic embryopathy. We investigated the concentrations of PPARdelta and its endogenous agonist prostaglandin (PG)I(2), as well as the effect of PPARdelta activation on lipid metabolism and PGE(2) concentrations in embryos from control and streptozotocin-induced diabetic rats during early organogenesis. Embryos from diabetic rats showed decreased concentrations of PPARdelta and its endogenous agonist PGI(2) when compared with controls. In embryos from control rats, the addition of the PPARdelta activators (cPGI(2) and PGA(1)) increased embryonic phospholipid levels and de novo phospholipid synthesis studied using (14)C-acetate as a tracer. PGE(2) formed from arachidonate released from phospholipid stores was also up-regulated by PPARdelta activators. In embryos from diabetic rats, reduced phospholipid synthesis and PGE(2) content were observed, and clearly up-regulated by cPGI(2) additions to values similar to those found in control embryos. These data suggest that PPARdelta may play an important role in lipid metabolic and signalling pathways during embryo organogenesis, developmental pathways that are altered in embryos from diabetic rats, possibly as a result of a reduction in levels of PPARdelta and its endogenous activator PGI(2).
Assuntos
Diabetes Mellitus Experimental/embriologia , Epoprostenol/metabolismo , Doenças Fetais/metabolismo , Metabolismo dos Lipídeos , Organogênese , PPAR delta/metabolismo , Prenhez , Animais , Dinoprostona/análise , Técnicas de Cultura Embrionária , Embrião de Mamíferos/anatomia & histologia , Embrião de Mamíferos/metabolismo , Epoprostenol/farmacologia , Feminino , Desenvolvimento Fetal/efeitos dos fármacos , Doenças Fetais/induzido quimicamente , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , PPAR delta/fisiologia , Gravidez , Gravidez em Diabéticas , Ratos , Ratos Wistar , Transdução de Sinais , EstreptozocinaRESUMO
Maternal diabetes significantly increases the risk of congenital malformation, a syndrome known as diabetic embryopathy. Nitric oxide (NO), implicated in embryogenesis, has been found elevated in embryos from diabetic rats during organogenesis. The developmental signaling molecules endothelin-1 (ET-1) and 15-deoxy delta(12,14)prostaglandin J2 (15dPGJ2) downregulate embryonic NO levels. In the presence of NO and superoxide, formation of the potent oxidant peroxynitrite may occur. Therefore, we investigated peroxynitrite-induced damage, ET-1 and 15dPGJ2 concentrations, and the capability of ET-1, 15dPGJ2 and prostaglandin E2 (PGE2) to regulate NO production in embryos from severely diabetic rats (streptozotocin-induced before pregnancy). We found intense nitrotyrosine immunostaining (an index of peroxynitrite-induced damage) in neural folds, neural tube and developing heart of embryos from diabetic rats (P < 0.001 vs controls). We also found reduced ET-1 (P < 0.001) and 15dPGJ2 (P < 0.001) concentrations in embryos from diabetic rats when compared with controls. In addition, the inhibitory effect of ET-1, 15dPGJ2 and PGE2 on NO production found in control embryos was not observed in embryos from severely diabetic rats. In conclusion, both the demonstrated peroxynitrite-induced damage and the altered levels and function of multiple signaling molecules involved in the regulation of NO production provide supportive evidence of nitrosative stress in diabetic embryopathy.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Embrião de Mamíferos/metabolismo , Óxido Nítrico/metabolismo , Organogênese/fisiologia , Gravidez em Diabéticas/metabolismo , Tirosina/análogos & derivados , Animais , Embrião de Mamíferos/química , Endotelina-1/análise , Feminino , Imuno-Histoquímica/métodos , Nitratos/análise , Nitritos/análise , Gravidez , Prostaglandina D2/análogos & derivados , Prostaglandina D2/análise , Ratos , Ratos Wistar , Tirosina/análiseRESUMO
15-Deoxy-Delta(12,14)-prostaglandin J2 (15dPGJ2) is a peroxisome proliferator-activated receptor (3) (PPAR(3)) ligand that regulates lipid homeostasis and has anti-inflammatory properties in many cell types. We postulated that 15dPGJ2 may regulate lipid homeostasis and nitric oxide (NO) levels in term placental tissues and that alterations in these pathways may be involved in diabetes-induced placental derangements. In the present study, we observed that, in term placental tissues from streptozotocin-induced diabetic rats, 15dPGJ2 concentrations were decreased (83%) and immunostaining for nitrotyrosine, indicating peroxynitrite-induced damage, was increased. In the presence of 15dPGJ2, concentrations of nitrates/nitrites (an index of NO production) were diminished (40%) in both control and diabetic rats, an effect that seems to be both dependent on and independent of PPAR(3) activation. Exogenous 15dPGJ2 did not modify lipid mass, but decreased the incorporation of (14)C-acetate into triacylglycerol (35%), cholesteryl ester (55%) and phospholipid (32%) in placenta from control rats, an effect that appears to be dependent on PPAR(3) activation. In contrast, the addition of 15dPGJ2 did not alter de novo lipid synthesis in diabetic rat placenta, which showed decreased levels of PPAR(3). We conclude that 15dPGJ2 modulates placental lipid metabolism and NO production. The concentration and function of 15dPGJ2 and concentrations of PPAR(3) were altered in placentas from diabetic rats, anomalies probably involved in diabetes-induced placental dysfunction.