Effect of high-fat diet on liver and placenta fatty infiltration in early onset preeclampsia-like mouse model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Preeclampsia, especially early onset of preeclampsia (PE), is a common and serious disorder with high maternal and perinatal morbidity and mortality. Dietary factor is one of the most important factors which may affect the occurrence and development of the disease. The aim of this study is to investigate the effects of dietary factors on pathological changes of liver and placenta in preeclampsia-like mouse model by establishing the model at multiple stages of gestation.</p><p><b>METHODS</b>Wild-type (WT) mice were injected subcutaneously with nitric oxide synthase (NOS) inhibitor L-arginine methyl ester (L-NAME, 50 mg×kg(-1)×d(-1)) to establish PE-like model (L-NAME group) at early-, mid-, and late-pregnant periods respectively; simultaneously, the control mice were injected with normal saline (NS group). All the groups were divided into subgroups, standard chow group (SC), and high-fat diet group (HF). ApoE(-/-) pregnant mice served as a control group. Systolic blood pressure (SBP), urine protein, and histopathologic changes of placenta and liver in all groups were observed and statistically analyzed.</p><p><b>RESULTS</b>In WT and apoE(-/-) L-NAME subgroups, blood pressure and urine protein were significantly higher than those in all the gestational age matched NS groups (P < 0.05). Compared to other groups, remarkable liver fatty infiltration and lipid storage in placenta were found in early- and mid-L-NAME subgroups in apoE(-/-) mice (P < 0.05), especially in the early- and mid-HF+L-NAME subgroups in apoE(-/-) mice (P < 0.05). More lipid storage droplets both in liver and placenta were found in ApoE(-/-) mice than that of WT groups (P < 0.05). Morphology histopathologic examination of placentas showed varying degrees of fibrinoid necrosis and villous interstitial edema in early- and mid-L-NAME both in HF and SC of apoE(-/-) and WT subgroups compared to NS controls (P < 0.05). But there was no significant difference between HF and SC subgroups (P > 0.05), and no difference between apoE(-/-) and WT groups (P > 0.05).</p><p><b>CONCLUSIONS</b>Preeclampsia-like conditions could be induced by L-NAME in mice at different gestational stages. Both WT and apoE(-/-) genotype mice with preeclampsia-like symptoms in early and mid stages of pregnancy presented lipid deposition in the placenta and hepatic fatty infiltration. To alter the environmental condition by feeding high-fat diet was harmful to the mother and the fetus. High-fat diet aggravated the impact of liver fatty infiltration at early and mid gestational stages especially in the apoE(-/-) mouse model. These results further revealed the association between early-onset preeclampsia and the dysoxidation of fatty acids.</p>

Inhibition of nitric oxide synthase lowers fatty acid oxidation in preeclampsia-like mice at early gestational stage / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Preeclampsia is one of hypertensive disorders in pregnancy. It is associated with abnormal lipid metabolism, including fatty acid oxidation metabolism. Long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) plays an indispensable role in the oxidation of fatty acids. It has been reported that nitric oxide (NO) is one of the regulatory factors of the fatty acid oxidation pathway. The aim of this research was to investigate whether the nitric oxide synthase (NOS) inhibitor L-NAME may cause down-regulation of LCHAD in the pathogenesis of preeclampsia.</p><p><b>METHODS</b>Pregnant wild-type (WT) mice were treated with L-NAME or normal saline (NS) during gestation days 7 - 18 (early group), days 11 - 18 (mid group) and days 16 - 18 (late group), and apoE-/- mice served as a control. Systolic blood pressure (SBP), urine protein, feto-placental outcome, plasma lipid levels and NO concentrations were measured, and the expression of mRNA and protein for LCHAD in placental tissue were determined by real-time polymerase chain reaction (RT-PCR) and Western blotting, respectively.</p><p><b>RESULTS</b>In WT and apoE-/- mice, SBP and urinary protein increased following L-NAME injection. Fetal and placental weights and NO concentrations were reduced and total cholesterol, triglycerides and free fatty acid levels were increased in early and mid L-NAME groups in WT and apoE-/- mice, compared with the NS group. There was no significant difference between the late L-NAME group and NS group. RT-PCR and Western blotting analysis showed that the mRNA and protein levels of LCHAD expression were significantly down-regulated in the early and mid L-NAME groups but not in the late L-NAME group in the WT and apoE-/- mice compared with the corresponding NS groups.</p><p><b>CONCLUSIONS</b>Inhibition of NO in early and mid gestation in mice may cause hyperlipidemia and suppression of fatty acid oxidation, whereas preeclampsia-like conditions in late gestation may be a maternal vascular response to inhibition of NO.</p>

Effects of preeclampsia-like symptoms at early gestational stage on feto-placental outcomes in a mouse model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Early and late-onset preeclampsia is thought to be different disease entities. This study aimed to determine the effects of early-onset preeclampsia-like symptoms on feto-placental outcomes and the adverse impacts of various factors on placental and fetal growth and development at different gestational stages in a mouse model.</p><p><b>METHODS</b>Pregnant C57BL/6J mice were divided into control and preeclampsia (PE) groups, and injected subcutaneously with the nitric oxide synthase inhibitor L-arginine methyl ester (L-NAME) 50 mgxkg(-1)d(-1). The PE group was divided into early-, mid- and late-PE groups with L-NAME injections starting on days 7, 11 and 16 of pregnancy, respectively. Corresponding control groups were injected with saline at the same time points. Blood pressure was measured until days 14 and 18, when the fetuses and placentas were removed under anesthesia. Blood pressure, urinary protein, and fetal and placental conditions were analyzed.</p><p><b>RESULTS</b>Blood pressure and urinary protein increased following L-NAME injection. The fetal survival rate and fetal weight were reduced and the fetal absorption rate was increased in the early-PE group on days 14 and 18 of pregnancy, compared with the control group. There were no significant differences in these parameters between the late-PE group and the respective control group. Placental weights in the early- and mid-PE groups were significantly reduced at days 14 and 18 of pregnancy compared with the control groups, but there was no significant difference in placental weight between the late-PE group and the respective control group. Morphologic examination of placentas from the early- and mid-PE groups showed varying degrees of fibrinoid necrosis and villous interstitial edema, but no significant pathologic changes were found in the placentas from the late-PE or control groups.</p><p><b>CONCLUSION</b>Preeclampsia-like symptoms occurring during the early stage of pregnancy are more likely to affect placental and fetal development, whereas late onset preeclampsia-like symptoms have a direct impact on the mothers.</p>