Abstract 15: Repopulation of CA1 Region in the Hippocampus is Accompanied by Increased Diameter and Reduced Glial Scarring After 20 Weeks of Survival in an 8 Min Ventricular Fibrillation Cardiac Arrest Rat Model

Background: The CA1 region of hippocampus is specifically vulnerable to global ischemia and is depopulated 14 days after 8min ventricular fibrillation cardiac arrests (VF-CA) and conventional resuscitation in a rat model. We have previously reported on the pyramidal cell repopulation of the CA1 region after long term survival after cardiac arrest in two thirds of animals. (Circulation. 2014;130:A80) The aim of this study was to investigate the distribution of microglia and astrocytes in the CA1 region of rat hippocampus after CA and to measure its diameter. Methods: After 8 min of VF-CA male Sprague-Dawley rats received mechanical chest compressions for 2 min and epinephrine 20 μg/kg. The animals were defibrillated thereafter every 2 min to achieve return of spontaneous circulation. Animals surviving with favorable neurologic recovery were sacrificed 140 days after CA (n=12, 8 with neuronal repopulation (R), 4 without R (nonR)) and compared to 14 day survivors (n=6) and control animals (n=20). Results: Mi...