This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Nishigori, H. Articles by Richardson, B. S. Search for Related Content PubMed PubMed Citation Articles by Nishigori, H. Articles by Mazzuca, D. M. Articles by Nygard, K. L. Articles by Han, V. K. Articles by Richardson, B. S. Social Bookmarking                         What's this?

BDNF and TrkB in the Preterm and Near-term Ovine Fetal Brain and the Effect of Intermittent Umbilical Cord Occlusion

Departments of Obstetrics and Gynaecology, The Children's Health Research Institute, The University of Western Ontario, London, Canada

Delfina M. Mazzuca, MSc

Department of Pediatrics, The Children's Health Research Institute, The University of Western Ontario, London, Canada

Karen L. Nygard, AHT

Department of Pediatrics The Children's Health Research Institute, The University of Western Ontario, London, Canada

Victor K. Han, MD

Department of Pediatrics, The Children's Health Research Institute, The University of Western Ontario, London, Canada

Bryan S. Richardson, MD, FRCS(C)

Departments of Obstetrics and Gynaecology, The Children's Health Research Institute, The University of Western Ontario, London, Canada, brichar1@ uwo.ca, Department of Physiology and Pharmacology, The Children's Health Research Institute, The University of Western Ontario, London, Canada

We have determined the developmental change in immunoreactivity for brain-derived neurotrophic factor and its high-affinity tyrosine kinase receptor, TrkB, in the ovine fetal brain with advancing gestation and in response to intermittent umbilical cord occlusion, which might then contribute to adverse neurodevelopment. Fetal sheep (control and experimental groups at 0.75 and 0.90 of gestation) were studied over 4 days with umbilical cord occlusions performed in the experimental group animals by complete inflation of an occluder cuff for 90 seconds every 30 minutes for 3 to 5 hours each day. Animals were then euthanized and the fetal brains perfusion fixed and prepared for subsequent histology with the distribution of brain-derived neurotrophic factor and tyrosine kinase receptor immunoreactivity determined by immunohistochemistry. In the control group animals brain-derived neurotrophic factor immunoreactivity decreased in the gray matter, thalamus, and hippocampus but increased in the white matter, while tyrosine kinase receptor immunoreactivity decreased in all regions (most P < .01), with advancing gestation consistent with the developmental change from neurogenesis/gliagenesis to myelination over this time period. Intermittent umbilical cord occlusion as studied with severe but limited hypoxemia resulted in a variable decrease in brain-derived neurotrophic factor and tyrosine kinase receptor immunoreactivity for all brain regions in the preterm animals (most P < .01) when protein turnover is higher, but a selective increase in brain-derived neurotrophic factor immunoreactivity in the hippocampus of the near-term animals consistent with a heightened vulnerability for necrotic/apoptotic injury at this time. As such, brain-derived neurotrophic factor—tyrosine kinase receptor in the ovine fetal brain may be altered with intermittent hypoxic insults over the latter part of pregnancy with potential for longer term neurologic consequences.

Key Words: Brain development • growth factors • hypoxia.

Reproductive Sciences, Vol. 15, No. 9, 895-905 (2008)
DOI: 10.1177/1933719108324135


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?