150 Differencial Distribution of Cell Death in Hypoxic-Ischemic Brain Injury in Preterm Lambs

Abstract

The brain damage produced during the hypoxic-ischemic event is one of the major causes of mortality and neurological morbidity in premature and term newborns. The aim of this work was to evaluate the distribution of cell death in the first hours after HI brain injury in fetal lambs. Fifteen near-term lambs at 80–90% of gestation were assigned to two hypoxic-ischemic groups with or without life support (3 h), and a healthy one. Hypoxia-ischemia was induced by partial cord occlusion of the umbilical cord (60min). Lambs were sacrificed and brain fixed by perfusion. Light and transmission electron microscopy, and the TUNEL method for apoptosis were performed. In both treated groups we have observed scattered neurons with necrotic changes and oligodendrocytes-like cells with apoptosis. Necrotic cells were located mainly in subcortical areas whereas apoptotic cells were placed in white and gray matter of cortical areas. Our results suggest that cell death by necrosis involves elements which participate in extrapiramidal pathway and that apoptotic cells were implicated in cortical pathway alteration. Thus, the hipoxic-ischemic injury would produce a disorder in the common final pathway and motor impairment in preterm lambs. This work has been supported by grants from Fondo de Investigacion Sanitaria, Ministerio de Sanidad (FIS01/0110–2), and from the Universidad del Pais Vasco (1/UPV075.327-E-14885/2002 and 9/UPV00077.327–15330/2003 HILARIO).