Oxygen and Glucose Deprivation in an Organotypic Hippocampal Slice Model of the Developing Rat Brain: The Effects on N-Methyl-d-Aspartate Subunit Composition

Abstract

Organotypic hippocampal slices (OHS) are commonly used to screen for neuroprotective effects of pharmacological agents relevant to pediatric brain injury. The importance of donor rat pup age and N-methyl-D-aspartate (NMDA) receptor subunit composition have not been addressed. In this study, we evaluated the age-dependent effect of oxygen-glucose deprivation (OGD) in the developing rat brain and determined whether OGD modulates the NMDA receptor subunit composition. OHS were prepared from rat pups on postnatal days (PND) 4, 7, 14, and 21 and cultured 7 days in vitro. The slices were exposed to OGD for durations of 5-60 min. After 24 and 72 h, OHS survival and NMDA subunit composition were assessed. Cell death was evident in OHS prepared from PND 14 and 21 rat pups (P < 0.001) with OGD durations of 5 and 10 min, respectively. In OHS prepared from PND7 rat pups, neurodegeneration was not evident until 20 min OGD (P < 0.001). Exposure to OGD in OHS prepared from PND4 and PND7 rat pups was associated with a transition in the NMDA receptor subunit composition from NR2B predominant to NR2A predominant subunit composition. This in vitro neonatal rat pup investigation using OHS supports both an age and an NMDA receptor subunit composition-dependent relationship between OGD and neuronal cell death.