Treatment with Iodine in Pregnant Rats with Marginal Iodine Deficiency Improves Cell Migration in the Developing Brain of the Progeny

Influence of Cerebral Vasodilation on Blood Reelin Levels in Growth Restricted Fetuses

Fetal growth restriction (FGR) is one of the most important obstetric pathologies. It is frequently caused by placental insufficiency. Previous studies have shown a relationship between FGR and impaired new-born neurodevelopment, although the molecular mechanisms involved in this association have not yet been completely clarified. Reelin is an extracellular matrix glycoprotein involved in development of neocortex, hippocampus, cerebellum and spinal cord. Reelin has been demonstrated to play a key role in regulating perinatal neurodevelopment and to contribute to the emergence and development of various psychiatric pathologies, and its levels are highly influenced by pathological conditions of hypoxia. The purpose of this article is to study whether reelin levels in new-borns vary as a function of severity of fetal growth restriction by gestational age and sex. We sub-grouped fetuses in: normal weight group (Group 1, n = 17), FGR group with normal umbilical artery Doppler and cerebral redistribution at middle cerebral artery Doppler (Group 2, n = 9), and FGR with abnormal umbilical artery Doppler (Group 3, n = 8). Our results show a significant association of elevated Reelin levels in FGR fetuses with cerebral blood redistribution compared to the normal weight group and the FGR with abnormal umbilical artery group. Future research should focus on further expanding the knowledge of the relationship of reelin and its regulated products with neurodevelopment impairment in new-borns with FGR and should include larger and more homogeneous samples and the combined use of different in vivo techniques in neonates with impaired growth during their different adaptive phases.

Assessment of the effects of repeated doses of potassium iodide intake during pregnancy on male and female rat offspring using metabolomics and lipidomics

Preparedness for nuclear accident responsiveness includes interventions to protect pregnancies against prolonged exposure to radioactive iodine. The aim of this study was to investigate a new design consisting of repeated administration of potassium iodide (KI, 1 mg/kg) for 8 days in late pregnancy gestational day 9-16 (GD9-GD16) in rats. The later-life effects of this early-life iodine thyroid blocking (ITB) strategy were assessed in offspring two months afterbirth. Functional behavioral tests including forced swimming test (FST) and rotarod test (RRT) in rats of both genders showed lower FST performance in KI-treated females and lower RRT performance in KI-treated male pups. This performance decline was associated with metabolic disruptions in cortex involving amino acid metabolism, tyrosine metabolism, as well as docosahexaenoic acid (DHA) lipids and signaling lipids in males and females. Beyond these behavior-associated metabolic changes, a portion of the captured metabolome (17-25%) and lipidome (3.7-7.35%) remained sensitive to in utero KI prophylactic treatment in both cortex and plasma of post-weaning rats, with some gender-related variance. Only part of these disruptions was attributed to lower levels of TSH and T4 (males only). The KI-induced metabolic shifts involved a broad spectrum of functions encompassing metabolic and cell homeostasis and cell signaling functions. Irrespective Regardless of gender and tissues, the predominant effects of KI affected neurotransmitters, amino acid metabolism, and omega-3 DHA metabolism. Taken together, data demonstrated that repeated daily KI administration at 1 mg/kg/day for 8 days during late pregnancy failed to protect the mother-fetus against nuclear accident radiation. Abbreviations: CV-ANOVA: Cross-validation analysis of variance; DHA: Docosahexaenoic acid; FST: Forced swimming test; FT3: plasma free triiodothyronine; FT4: plasma free thyroxine; GD: Gestational day; ITB: Iodine thyroid blocking; KI: potassium iodide; LC/MS: Liquid chromatography coupled with mass spectrometry; MTBE: Methyl tert-butyl ether; m/z: mass-to-charge ratio; PLS-DA: Partial least squares-discriminant analysis; PRIODAC: Repeated stable iodide prophylaxis in accidental radioactive releases; RRT: Rotarod test; TSH: Thyroid-stimulating hormone; VIP: Variable importance in projection.

Maternal marginal iodine deficiency delays cerebellar Bergmann glial cell development in rat offspring: Involvement of Notch signaling pathway

During early pregnancy, iodine deficiency (ID) is linked to adverse effects on child motor and psychomotor function. Maternal marginal ID has become a common public health problem. It is unclear whether marginal ID influences the development of the cerebellum or its underlying mechanisms. Thus, the purpose of this study was to determine the effects of marginal ID on the development of cerebellar Bergmann glial cells (BGs) and investigate the activation of the Notch signaling pathway, which is crucial for the development and morphology of BGs. We treated Wistar rats with an ID diet (iodine content 60 ± 1.5 ng/g) supplemented with deionized water containing different concentrations of potassium iodide (KI) (183, 117, and 0 μg/L for the control, marginal ID, and severe ID groups, respectively) during pregnancy and lactation. We explored the morphology of the BGs by Golgi-Cox staining and immunofluorescence and investigated the Notch signaling pathway using western blot. Our results showed that the marginal ID and severe ID groups had decreased cerebellar BG fiber lengths (P < 0.05 and 0.01, respectively) and numbers (P < 0.01 for both) on postnatal day (PN) 7, PN14, and PN21 compared to the control group. Moreover, the data showed that severe ID significantly reduced Dll1, Notch1, RBP-Jκ, and BLBP protein levels at all three time points. Marginal ID slightly reduced the expression of Notch1 on PN7 (P < 0.05) and PN21 (P < 0.01), RBP-Jκ on PN14 (P < 0.01) and PN21 (P < 0.05), and BLBP on PN7 (P < 0.05). There was no significant difference in Dll1 protein levels between the marginal ID and control groups at any time point. Our study suggests that marginal ID leads to mild damage to BG morphogenesis in the cerebellum. The abnormal regulation of the Notch signaling pathway may be involved in the damage to BGs.

Maternal marginal iodine deficiency limits dendritic growth of cerebellar purkinje cells in rat offspring by NF-κB signaling and MAP1B

Iodine deficiency (ID) during early pregnancy had an adverse effect on children's psychomotor and motor function. It is worth noting that maternal marginal ID tends to be a common public health problem. Whether marginal ID potentially had adverse effects on the development of cerebellum and the underlying mechanisms remain unclear. Therefore, our aim was to study the effects of marginal ID on the dendritic growth in filial cerebellar Purkinje cells (PCs) and the underlying mechanism. In the present study, we established Wistar rat models by feeding dam rats with a diet deficient in iodine and deionized water supplemented with potassium iodide. We examined the total dendritic length using immunofluorescence, and Western blot analysis was conducted to investigate the activity of nuclear factor-κB (NF-κB) signaling and microtubule-associated protein 1B (MAP1B). Our results showed that marginal ID reduced the total dendritic length of cerebellar PCs, slightly down-regulated the activity of NF-κB signaling and decreased MAP1B in cerebellar PCs on postnatal day (PN) 7, PN14, and PN21. Our study may support the hypothesis that decreased T₄ induced by marginal ID limits PCs dendritic growth, which may involve in the disturbance of NF-κB signaling and MAP1B on the cerebellum. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1241-1251, 2017.