Effects of preeclampsia-like symptoms at early gestational stage on feto-placental outcomes in a mouse model

Background 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. Methods 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 mg·kg^-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. Results 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. Conclusion 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.

Inhibition of nitric oxide synthase lowers fatty acid oxidation in ~reeclampsia-like mice at early gestational stage

Background Preeclampsia is one of hypertensive disorders in pregnancy. It is associated with abnormal lipid metabolism, including fatty acid oxidation metabolism. Long chain 3-hydroxyacyI-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.Methods 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.Results 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.Conclusions 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.