title: Dopamine treatment during acute hypoxia is neuroprotective in the developing sheep brain.
abstract: Dopamine is often used to treat hypotension in preterm infants; these infants are at risk of developing brain injury due to impaired autoregulation and cerebral hypoperfusion. However the effects of dopamine on the immature brain under conditions of cerebral hypoxia are not known. We hypothesized that pretreatment with dopamine would protect the immature brain from injury caused by cerebral hypoxia. Preterm fetal sheep were used to determine the effects of intravenous dopamine on hypoxia-induced brain injury. In 16 pregnant sheep at 90days of gestation (0.6 of term, term=147days) catheters were implanted aseptically into the fetal carotid artery and jugular vein; an inflatable occluder was placed loosely around the umbilical cord for later induction of fetal hypoxemia. At 5days after surgery, dopamine (10μg/kg/min, n=7 fetuses) or saline (n=9 fetuses) was infused for 74h. Two hours after commencing the dopamine/saline infusion, we induced umbilical cord occlusion (UCO) for up to 25min to produce fetal asphyxia. Fetuses were allowed to recover, and brains were collected 72h later for assessment of neuropathology. Un-operated twin fetuses were used as age-matched non-UCO controls (n=8). In UCO+saline fetuses, microglial and apoptotic cell density in the subcortical and periventricular white matter, caudate nucleus and hippocampus was greater than that in age-matched controls; oxidative stress was elevated in the subcortical and periventricular white matter and caudate nucleus compared to that in age-matched controls. In UCO+dopamine fetuses microglial density and oxidative stress in the cerebral white matter and caudate nucleus were not different to that of age-matched controls. Apoptotic cell death was decreased in the cerebral white matter of UCO+dopamine brains, relative to UCO+saline brains. We conclude that pretreatment with dopamine does not exacerbate hypoxia-induced injury in the immature brain and may be neuroprotective because it led to decreased apoptosis, oxidative stress and neuroinflammation in the cerebral white matter and decreased neuroinflammation in the caudate nucleus.
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Brew
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Azhan
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: I
authors.initials: I
authors.lastname: den Heijer
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Boomgardt
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: G I
authors.initials: GI
authors.lastname: Davies
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: I
authors.initials: I
authors.lastname: Nitsos
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: S L
authors.initials: SL
authors.lastname: Miller
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
authors.forename: A M
authors.initials: AM
authors.lastname: Walker
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia; Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia.
authors.forename: D W
authors.initials: DW
authors.lastname: Walker
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia; Monash Newborn, Monash Medical Centre, Melbourne, Australia; Department of Pediatrics, Monash University, Melbourne, Australia. Electronic address: flora.wong@monash.edu.
authors.forename: F Y
authors.initials: FY
authors.lastname: Wong
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000196:embryology / Q000254:growth & development / Q000473:pathology; D001930:Brain Injuries / Q000209:etiology* / Q000517:prevention & control*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004195:Disease Models, Animal; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D004622:Embryo, Mammalian; D005260:Female; D005312:Fetal Blood / Q000187:drug effects; D005311:Fetal Hypoxia / Q000150:complications* / Q000188:drug therapy; D006339:Heart Rate / Q000187:drug effects; D002534:Hypoxia, Brain / Q000150:complications* / Q000188:drug therapy; D008840:Microfilament Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D011247:Pregnancy; D012756:Sheep
chemical_list: C491049:Aif1 protein, mouse; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D004298:Dopamine
keywords: dopamine; hypotension; inotrope; microglia; preterm brain injury; white matter