Ultraprofound cerebral hypothermia and blood substitution with an acellular synthetic solution maintains neuronal viability in rat hippocampus

The acute effects of ultraprofound hypothermia and blood substitution (Uf-I BS) on neuronal cell viability were examined in adult rat hippocampus, a br ain region particularly vulnerable to ischemic cell death. UHBS was perform ed using either artificial cerebrospinal fluid (ACSF) or Hypothermosol, an "intracellular-type" hypothermic preservation solution. After the procedure , the hippocampus was sliced and tested for cellular viability using a comb ination of cellular fluorochromes that are markers for live cells (acridine orange) and dead cells (propidium iodide). UHBS with ACSF resulted in a va riable degree of neuronal death within the hippocampal subfields CA1/CA3, a nd dentate granular layer and hilus (CA4). In contrast, UHBS with Hypotherm osol consistently resulted in hippocampal slices with only mild neuronal de ath. Our results of preserved hippocampal neuronal viability with use of UH BS and Hypothermosol support the demonstrated central nervous system (CNS) protective effects of UHBS and Hypothermosol when used during prolonged car diac arrest. The results of this study also suggest that UHBS and Hypotherm osol may be useful in the preparation and maintenance of viable hippocampal tissue for physiological studies, especially those involving aged animals, which are particularly vulnerable to hypoxic-ischemic cellular injury.