The effect of cerebral hypothermia on white and grey matter injury induced by severe hypoxia in preterm fetal sheep.
J Physiol
; 578(Pt 2): 491-506, 2007 Jan 15.
Article
en En
| MEDLINE
| ID: mdl-17095565
ABSTRACT
Prolonged, moderate cerebral hypothermia is consistently neuroprotective after experimental hypoxia-ischaemia; however, it has not been tested in the preterm brain. Preterm (0.7 gestation) fetal sheep received complete umbilical cord occlusion for 25 min followed by cerebral hypothermia (fetal extradural temperature reduced from 39.4 +/- 0.3 to 29.5 +/- 2.6 degrees C) from 90 min to 70 h after the end of occlusion or sham cooling. Occlusion led to severe acidosis and profound hypotension, which recovered rapidly after release of occlusion. After 3 days recovery the EEG spectral frequency, but not total intensity, was increased in the hypothermia-occlusion group compared with normothermia-occlusion. Hypothermia was associated with a significant overall reduction in loss of immature oligodendrocytes in the periventricular white matter (P < 0.001), and neuronal loss in the hippocampus and basal ganglia (P < 0.001), with suppression of activated caspase-3 and microglia (isolectin-B4 positive). Proliferation was significantly reduced in periventricular white matter after occlusion (P < 0.05), but not improved after hypothermia. In conclusion, delayed, prolonged head cooling after a profound hypoxic insult in the preterm fetus was associated with a significant reduction in loss of neurons and immature oligodendroglia, with evidence of EEG and haemodynamic improvement after 3 days recovery, but also with a persisting reduction in proliferation of cells in the periventricular region. Further studies are required to evaluate the long-term impact of cooling on brain growth and maturation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Hipoxia-Isquemia Encefálica
/
Hipoxia Fetal
/
Feto
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Hipotermia Inducida
Límite:
Animals
/
Pregnancy
Idioma:
En
Revista:
J Physiol
Año:
2007
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda