title: Effect of nitric oxide deficiency on tissue-type plasminogen activator expression in the umbilical cord in a pregnancy-induced hypertension rat model.
abstract: OBJECTIVE
  Our study investigates the effects of nitric oxide (NO) deficiency during pregnancy on coagulation and fibrinolysis balance in fetal circulation.
  
  
  METHODS
  Pregnant rats were treated with or without oral N(G)-nitro-l-arginine methyl ester (L-NAME). Systolic blood pressure (SBP) and urinary protein were measured. On gestational day 20, mRNA levels of tissue-type plasminogen activator (tPA), tissue factor (TF), and TF pathway inhibitor (TFPI) in the umbilical cord, placenta, and maternal aorta were evaluated. Immunohistochemical staining of the placenta for PA inhibitor-1 (PAI-1) was performed.
  
  
  RESULTS
  L-NAME treatment in pregnant rats caused significant SBP elevation and severe proteinuria. In the L-NAME-treated group, weights of fetuses and placentae were diminished. tPA mRNA expression decreased in the umbilical cord and placenta, whereas TF and TFPI mRNA levels did not change. Intense PAI-1 immunoreactivity was observed in a part of degenerated placenta. In the aorta, tPA mRNA expression increased in the L-NAME-treated group, while TFPI mRNA levels were lower than in controls.
  
  
  CONCLUSIONS
  NO deficiency during pregnancy decreased tPA mRNA expression in the umbilical cord and placenta but not in the maternal aorta. Imbalance between coagulation and fibrinolysis in fetal and maternal circulations may, at least in part, contribute to fetal growth restriction.
authors.affiliation: Department of Nutrition, Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori 030-8505, Japan. Electronic address: y_mukai@auhw.ac.jp.
authors.forename: Yuuka
authors.initials: Y
authors.lastname: Mukai
authors.affiliation: Department of Nutrition, Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori 030-8505, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Sato
keywords: Animal model; Fetal growth restriction; Hemostatic system; Nitric oxide deficiency; Pregnancy-induced hypertension; Tissue-type plasminogen activator