title: Long-term effects of a midgestational asphyxial episode in the ovine fetus.
abstract: We and others have shown previously that fetuses at midgestation can survive 30 min of complete umbilical cord occlusion, although hydrops fetalis (or gross fetal edema) results. To investigate whether this hydrops resolves by late gestation and if there are any long-term consequences of the asphyxial insult on the heart and kidneys, eight fetuses were subjected to 30 min of complete umbilical cord occlusion at 0.6 gestation (90 days; term 150 days) and were compared to a sham group (n = 10). During the occlusion period, fetuses became severely hypoxemic, hypercapnemic, and acidotic, with both blood pressure and heart rate decreasing. Most variables had returned to normal by 2-hr recovery. At 129 +/- 1 days of gestation, approximately 40 days post occlusion, some fetuses were still slightly hydropic as skin fold measurements were increased (P < 0.01), although fetal body weight was not different from the sham group. The two groups had similar heart and kidney weights, ventricular cardiac myocyte nucleation, and glomerular number. By contrast, brain weight was reduced by 37% (P < 0.001) and the cerebral lateral ventricles were grossly dilated. Lungs were 50% smaller than in sham fetuses (P < 0.001). Thus, the hydrops that develops at midgestation as a result of a severe asphyxial episode can, but does not always, fully resolve by late gestation. Also, while fetuses at midgestation can survive this asphyxial episode with no long-term impact in renal or cardiac size, nephron number, or cardiomyocyte nucleation, the brain and lungs are severely affected.
authors.affiliation: Department of Physiology and Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia. a.oconnell@student.unsw.edu.au
authors.forename: Amanda E
authors.initials: AE
authors.lastname: O'Connell
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Boyce
authors.forename: Vasumathy
authors.initials: V
authors.lastname: Kumarasamy
authors.forename: Rebecca
authors.initials: R
authors.lastname: Douglas-Denton
authors.forename: John F
authors.initials: JF
authors.lastname: Bertram
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Gibson
mesh_terms: D000138:Acidosis / Q000097:blood / Q000209:etiology; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure; D003250:Constriction; D004195:Disease Models, Animal; D004487:Edema / Q000097:blood / Q000209:etiology / Q000473:pathology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D047109:Fetal Development; D005311:Fetal Hypoxia / Q000097:blood / Q000473:pathology*; D005333:Fetus / Q000473:pathology*; D005865:Gestational Age; D006321:Heart / Q000196:embryology / Q000503:physiopathology; D006339:Heart Rate; D015160:Hydrops Fetalis / Q000097:blood / Q000209:etiology / Q000473:pathology*; D007668:Kidney / Q000196:embryology / Q000473:pathology; D008297:Male; D009206:Myocardium / Q000473:pathology; D009929:Organ Size; D011247:Pregnancy; D020127:Recovery of Function; D012756:Sheep; D013997:Time Factors; D014470:Umbilical Cord