Investigating the Role of In Utero Inflammation on Neurodevelopment in the Fetus and Offspring and the Neuroprotective Properties Afforded by Broccoli Sprouts

• Author / Creator

  Nguyen, Antoinette

• Introduction Maternal infection and inflammation leading to a fetal inflammatory response (FIR) is a risk factor for perinatal brain damage. Perinatal brain injury can lead to neurodevelopmental disorders, the sine quo non outcome parameter of which is cerebral palsy (CP). Despite advances in maternal and fetal medicine, no preventive therapy exists to deter in utero inflammation and subsequent development of CP. The objectives of this thesis are to: verify a model of fetal inflammation leading to phenotypic features of CP; identify the mechanisms involved in fetal inflammation leading to this phenotype, and; determine if consumption of broccoli sprouts (BrSp) can prevent the abnormalities induced by this model of inflammation. Methods Pregnant Long-Evans rats were injected with lipopolysaccharide (LPS, 200 μg/kg) on embryonic days (E)19 and 20 every 12 hours. Beginning on E14, dams were randomly divided to receive BrSp dietary supplementation in addition to their regular chow, or not. Dams (and offspring) were divided into four groups: 1) Saline (control), 2) Saline + BrSp, 3) LPS, and 4) LPS + BrSp. Pups born underwent a battery of neurodevelopmental reflex and behavioural testing from postnatal day (PD)3-PD21. Placentas and fetuses were isolated on E19 and E22 to undergo cytokine and neurotrophic factor analyses. Uterine and umbilical arteries were imaged on E21 and excised on E22 to analyze blood flow and artery function. Pup’s brains were harvested on PD1, 7, and 21 to undergo histological analyses. Results LPS pups born were growth restricted and smaller compared to Saline, Saline + BrSp, and LPS + BrSp pups. LPS pups were significantly delayed in several neurodevelopmental reflexes testing including hindlimb placing, cliff avoidance, and gait. LPS + BrSp pups performances on these reflexes were not different from controls. Furthermore, LPS and LPS + BrSp pups ambulated less following open field analyses. On PD21, a reduction in myelination was observed in the LPS and LPS + BrSp groups compared to Saline and Saline + BrSp. To confirm the model elicits a FIR, placentas and fetal brains were examined for changes to cytokine expression on E19 and E22. On E19, an increase in interleukin (IL)-1β, TNF-α, IL-6, and IL-10 was detected in the LPS and LPS + BrSp placentas. In the fetal brain, a significant increase in pro-IL-1β was detected on E22 in the LPS group compared to Saline, Saline + BrSp and LPS + BrSp groups. On PD1, the ratio of pro-inflammatory cytokines protein levels, normalized to IL-10, was analyzed. A reduction in the TNF-α/IL-10 and IL-6/IL-10 was identified in the brains of females in both LPS and LPS+ BrSp groups. Analyses of neurotrophic factor expression, a possible downstream target of the cytokines, revealed a significant decrease in nerve growth factor mRNA production in the fetal brains at E22 in the LPS and LPS + BrSp groups. A significant reduction in 2’,3’-cyclic-nucleotide 3’-phosphodiesterase, a marker of differentiated oligodendrocytes, was observed in the white matter of PD21 LPS pups. No other differences in maturation markers, utero- and umbilical-placental blood flow, and uterine artery vascular contractile and relaxation function were detected. Conclusions LPS induced maternal inflammation was sufficient to produce reflex and behavioural abnormalities in their offspring, with an early phenotype that is consistent with that of developmental disability and CP. An increased placental and fetal inflammatory response was observed along with a reduction in NGF production and 2’,3’-cyclic-nucleotide 3’-phosphodiesterase in LPS pups. BrSp dietary supplementation significantly prevented growth restriction and some developmental reflex delays, the upregulation in IL-1β mRNA, and 2’,3’-cyclic-nucleotide 3’-phosphodiesterase levels. The findings suggest that BrSp dietary supplementation during pregnancy is a novel, safe and efficacious preventive strategy in the challenge of treating cerebral palsy and the developmental disabilities.

• Subjects / Keywords

  • Interventions
  • Fetal inflammation
  • Broccoli sprouts
  • Cererbral palsy

• Graduation date

  2016-06:Fall 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3057D35Z

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.