Neonatal Hypoxia Ischemia Redistributes L1 Cell Adhesion Molecule into Rat Cerebellar Lipid Rafts

Hypoxic-ischemic encephalopathy (HIE) is a devastating disease with lifelong disabilities. Hypothermia is currently the only treatment. At term, the neonatal cerebellum may be particularly vulnerable to the effects of HIE. At this time, many developmental processes depend on lipid raft function. These microdomains of the plasma membrane are critical for cellular signaling and axon extension. We hypothesized that HIE alters the protein content of lipid rafts in the cerebellum. Postnatal day (PN) 10 animals, considered human term equivalent, underwent hypoxic-ischemic (HI) injury by a right carotid artery ligation followed by hypoxia. For some animals, LPS was administered on PN7 and hypothermia (HT) was conducted for 4 hours post-hypoxia. Lipid rafts were isolated from right and left cerebella. The percent of total L1 cell adhesion molecule in lipid rafts was determined 4 and 72 h after hypoxia. No sex differences were found. HI alone caused significant increases in the percent of L1 in lipid rafts which persisted until 72 h in the right but not the left cerebellum. A small but significant effect of LPS was detected in the left cerebellum 72 h after HI. Hypothermia had no effect. Lipid rafts may be a new target for interventions of HIE.