Abstract 362: Behavioral Testing With Morris Water Maze in Rats Resuscitated With Emergency Cardiopulmonary Bypass From 10 Min Ventricular Fibrillation Cardiac Arrest

Abstract

Background: Rodent models of cardiac arrest help to investigate detailed pathophysiologic mechanisms of cerebral ischemia and reperfusion. Sensitive neurologic and behavioral tests would enhance the ability of such models to evaluate possible beneficial effects of protective therapies. The Morris Water Maze (MWM) is a procedure to study spatial learning and memory. The aim of this study was to investigate behavioral testing with the MWM in rats resuscitated from ventricular fibrillation (VF) cardiac arrest (CA) via emergency cardiopulmonary bypass (ECPB). Methods: Sprague-Dawley rats (450g, male, anesthetized) were put into VF CA. After 10 min of CA the animals were resuscitated with ECPB, epinephrine and defibrillations and cooled to mild hypothermia (33°C) . Ten surviving animals with favorable neurologic recovery were compared to 8 healthy rats. MWM was performed in each animal 2 times on 4 consecutive days for maximal 60 s with a hidden platform in a 22°C cold water tank and on day 7 and 14 with the platform removed for memory testing. Results: The latency time to find the hidden platform decreased in the CPB group and the control group from 60(IQR 39-60) s and 60(IQR 60-60) s to 9(IQR 6-29) s and 10(IQR 6-19) s respectively (p=0.46). After removal of the platform the time within the target sector on day 7 in 60 s was 17±6 s and 22±5 s (p=0.08) and on day 14 12±4 s and 13±4 s (p=0.76) respectively. Conclusions: Spatial learning and memory in clinical neurologically intact animals resuscitated from a 10 min VF CA cooled to mild hypothermia was comparable to normal healthy controls. With this MWM setup learning was performed well, the remembrance of platform position was kept for one week in both groups equally.