title: Maternal magnesium sulfate fetal neuroprotective effects to the fetus: inhibition of neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells activation in a rodent model.
abstract: Maternal magnesium administration has been shown to protect the preterm fetus from white- and gray-matter injury, although the mechanism is unknown.
  
  
  
  The purpose of the study is to test the following hypotheses: (1) maternal infections/inflammation activate fetal neuronal N-methyl-D-aspartate receptors that up-regulate neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells pathways; and (2) maternal magnesium sulfate attenuates fetal brain neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells activation through N-methyl-D-aspartate receptors.
  
  
  
  Pregnant rats at embryonic day 16 and embryonic day 18 (n = 6, 48 total) received injections of intraperitoneal lipopolysaccharide 500 μg/kg or saline at time 0. Dams were randomized for treatment with subcutaneous magnesium sulfate (270 mg/kg) or saline for 2 hours prior to and following lipopolysaccharide/saline injections. At 4 hours after lipopolysaccharide administration, fetal brains were collected from the 4 treatment groups (lipopolysaccharide/saline, lipopolysaccharide/magnesium sulfate, saline/magnesium sulfate, saline/saline), and phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and chemokine (C-C motif) ligand 2 protein levels were determined by Western blot. An additional group of pregnant rats (n = 5) received N-methyl-D-aspartate-receptor antagonist following the lipopolysaccharide injection to study magnesium sulfate protective mechanism.
  
  
  
  Lipopolysaccharide (lipopolysaccharide/saline) significantly increased fetal brain phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and chemokine (C-C motif) ligand 2 protein levels compared to the saline/saline group at both embryonic day 16 (phosphoneuronal nitric oxide synthase 0.23 ± 0.01 vs 0.11 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.24 ± 0.01 vs 0.14 ± 0.01 U; chemokine (C-C motif) ligand 2 0.28 ± 0.01 vs .01 ± 0.01 U) and embryonic day 18 (phosphoneuronal nitric oxide synthase 0.28 ± 0.01 vs 0.12 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.12 ± 0.01 vs 0.1 ± 0.01 U; chemokine (C-C motif) ligand 2 0.27 ± 0.01 vs 0.11 ± 0.01 U). Magnesium sulfate treatment to lipopolysaccharide dams (lipopolysaccharide/magnesium sulfate) significantly decreased fetal brain phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells, and chemokine (C-C motif) ligand 2 protein levels compared to lipopolysaccharide/saline dams at both embryonic day 16 (neuronal nitric oxide synthase 0.17 ± 0.02 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.17 ± 0.03 U; chemokine (C-C motif) ligand 2 0.18 ± 0.01 U) and embryonic day 18 (phosphoneuronal nitric oxide synthase 0.1 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.09 ± 0.01 U; chemokine (C-C motif) ligand 2 0.21 ± 0.01 U). Notably, maternal lipopolysaccharide at embryonic day 16 activated nuclear factor kappa-light-chain-enhancer of activated B cells twice as often compared to dams induced at embryonic day 18. N-methyl-D-aspartate-receptor antagonist decreased fetal brain phosphoneuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells levels comparable to magnesium sulfate.
  
  
  
  Lipopolysaccharide-simulated inflammation during pregnancy may cause brain injury through activation of neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells pathways and, potentially, production of excitotoxic nitric oxide and inflammatory mediators. The increased susceptibility to brain injury in preterm fetuses may be due to enhanced nuclear factor kappa-light-chain-enhancer of activated B cells activation. Magnesium sulfate protective effects may be secondary, in part, to inhibition of neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells activation and decrease proinflammatory cytokine production through blocking nuclear factor kappa-light-chain-enhancer of activated B cells receptors.
authors.affiliation: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel. Electronic address: ronbel3@gmail.com.
authors.forename: Ron
authors.initials: R
authors.lastname: Beloosesky
authors.affiliation: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
authors.forename: Nizar
authors.initials: N
authors.lastname: Khatib
authors.affiliation: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Ginsberg
authors.affiliation: Department of Obstetrics and Gynecology, Hillel Yaffe Medical Center, Hadera, Israel.
authors.forename: Saja
authors.initials: S
authors.lastname: Anabosy
authors.affiliation: Department of Obstetrics and Gynecology, Hillel Yaffe Medical Center, Hadera, Israel.
authors.forename: Einat
authors.initials: E
authors.lastname: Shalom-Paz
authors.affiliation: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
authors.forename: Masha
authors.initials: M
authors.lastname: Dahis
authors.affiliation: Department of Obstetrics and Gynecology, Harbor-University of California, Los Angeles Medical Center, Torrance, CA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ross
authors.affiliation: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
authors.forename: Zeev
authors.initials: Z
authors.lastname: Weiner
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D018932:Chemokine CCL2 / Q000378:metabolism; D005260:Female; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000009:adverse effects; D008278:Magnesium Sulfate / Q000494:pharmacology*; D023421:Models, Animal; D016328:NF-kappa B / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011247:Pregnancy; D017207:Rats, Sprague-Dawley
chemical_list: D018932:Chemokine CCL2; D008070:Lipopolysaccharides; D016328:NF-kappa B; D018696:Neuroprotective Agents; D008278:Magnesium Sulfate; D019001:Nitric Oxide Synthase
keywords: brain injury; inflammation; magnesium sulfate; neuronal nitric oxide synthase; nuclear factor kappa-light-chain-enhancer of activated B cells