A RAT MODEL FOR HYPOXIC-ISCHEMIC BRAIN-DAMAGE IN VERY PREMATURE-INFANTS

We proposed that hypoxic-ischemic injury suffered on postnatal day 1 ( PI) in the newborn rat would yield significant and reproducible brain injury simulating that seen in a midgestation human brain. The P1 pup was subjected to ipsilateral common carotid ligation followed by 3.5 h of 6% O-2 and demonstrated consistent histological changes in the ips ilateral hemisphere. At P2 neuronal loss and edema were pronounced in cortex and caudate; edema subsequently declined by P3. Astrocytic and microglial reactivity were seen as early as 24 h after injury, and by P10 both were extensive in damaged areas. There was marked loss of whi te matter on the affected side. We have demonstrated a reproducible mo del of hypoxic-ischemic injury to the very immature brain that can be used to elucidate mechanisms of neuronal loss and periventricular leuk omalacia.