Cerebral blood flow and morphological changes after hypoxic-ischaemic injury in preterm lambs.
OBJECTIVE
To evaluate the effect of cerebral hypoxia-ischaemia induced by partial occlusion of the umbilical cord on the relationship of the regional cerebral blood flow and the cerebral cell death in near-term fetal lambs.


METHODS
Fifteen near-term lambs were assigned to two hypoxic-ischaemic groups with or without life support (3 h), and a healthy one. Hypoxia-ischaemia was induced by partial occlusion of the umbilical cord (60 min). Routine light and electron microscopy, and the TUNEL method for apoptosis were performed. Regional cerebral blood flow was measured by coloured microspheres. Cardiovascular, gas exchange and pH parameters were also evaluated.


RESULTS
Both hypoxic-ischaemic groups produced a transient acidosis and a decrease of base excess in comparison to the healthy group. Cortical and cerebellar zones, where the regional cerebral blood flow values were similar to baseline, showed an increased number of oligodendrocyte-like apoptotic cells. In contrast, in the inner zones, where regional cerebral blood flow was increased, the number of apoptotic cells did not increase. Necrotic neurons were observed in the basal nuclei, mesencephalon, pons and deep cerebellar nuclei.


CONCLUSIONS
Our results suggest that regional cerebral blood flow and the presence of apoptotic cells, 3 h after hypoxic-ischemic injury, are correlated.
Hilario
Enrique
E
Department of Cell Biology and Histology, University of the Basque Country, 48940 Leioa, Vizcaya, Spain. gcphiroe@lg.ehu.es
Rey-Santano
Mari Carmen
MC
Goñi-de-Cerio
Felipe
F
Alvarez
Francisco Jose
FJ
Gastiasoro
Elena
E
Mielgo
Victoria Eugenia
VE
Caballero
Amale
A
Valls-i-Soler
Adolfo
A
Gómez-Urquijo
Sonia
S
Alvarez
Antonia
A
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D002560:Cerebrovascular Circulation; D053938:DNA Fragmentation; D020925:Hypoxia-Ischemia, Brain / Q000473:pathology / Q000503:physiopathology*; D020287:In Situ Nick-End Labeling; D011659:Pulmonary Gas Exchange; D012756:Sheep