The Effect Of Stress Factor On Learning And Memory In Mild Head Injured Rats

ObjectiveTo investigate the effects of stress factor on learning and memory in mild head injury of rats in convalescence stage. Provide the experiment data for clinical studies. Methods44 rats were divided randomly into three groups : A. normal control group (14 cases), B. stress group(14 cases)and C. damaged group(16 cases). Animal model of mild head injury in rats was duplicated using a improved device of Hall's head injury installment. 1) the behavior changes of the damaged group were observed by using Bederson's, Longa's and sensorimotor function test at 2h, ld, 2d and 3d after the rats' head were injured.2) Learning and memory ability was detected with Morris Water Maze before and after head injured. 3) after the test, processed for Nissl staining, we can observed the decrease of Nissl bodies in frontal lobe, temporal lobe and hippocampus. ResultsBehavioral changes: The damage and stress group to appear the aggressive movement, slow-acting, fear person after injury. The damage group appears movement barrier, restores normally after 3ds.Place navigation : the learning and memory ability has obvious difference between test and normal control group( P < 0. 05) , but there are no-difference between injured and stress group. ( P > 0. 05) .Spatial probe test: The two groups (frighten and damaged group) all showed a spatial bias towards the training target quadrant, spending significantly more time searching there, unlike the normal group( P < 0. 05).Morphological observe: In the frighten and damaged groups, the Nissl bodies in frontal lobe, temporal lobe and hippocampalCA1, CA3 are decreased compared to the normal group. ConclusionsThe stress factor may play an important role in learning and memory impairment after stress insult in rats.