Hypoxic preconditioning reduces apoptosis in a rat model of immature brain hypoxia-ischaemia.

Hypoxic events are common in newborns but their consequences on brain development have not been demonstrated. It has been reported that in newborn animal models of cerebral hypoxic-ischaemic insult, short-term hypoxia before the insult completely prevented brain damage. The mechanisms of this brain tolerance have not been fully elucidated. Using a rat model of hypoxic preconditioning at day 6 followed by carotid ligation and hypoxic insult at day 7, we found a decrease in the number of apoptotic cells 24 and 48 h after the insult in the striatum, hippocampus and cortex. We demonstrated here that regulation of apoptotic cell death is one of the mechanisms involved in tolerance to hypoxia-ischaemia induced by hypoxic preconditioning.