The vulnerability of the fetal sheep brain to hypoxemia at mid-gestation

Abstract

Our aim was to test the hypothesis, that a brief episode of hypoxemia near mid-gestation in fetal sheep will result in damage to the fetal brain with the extent and type of damage in any particular region being related to the developmental processes occurring at the time of the insult. Hypoxemia was induced, sufficient to reduce arterial O2 content by approximately 50%, by restricting utero-placental blood flow in 14 chronically catheterised fetuses for 6 h or 12 h at 84 days of gestation (term 145-8 days). Age- matched fetuses (n = 14; 4 operated and 10 unoperated) were used as controls. Fetuses were killed 7 days after being exposed to hypoxemia, and brains removed for histological analysi..