Behavioral effects and repercussion in memory acquisition induced for the continuous treadmill training after global cerebral ischemia in gerbils evaluated by the inhibitory avoidance task test

Abstract

The neurons of Nervous Central System are exposed to ischemic events that cause neuronal damages in vulnerable regions of the brain. The hipocampal region, which plays an important role in learning and memory, is also exposing to these damages. Studies indicate that the bilateral global ischemia by occlusion of the external carotides arteries induces neuronal cellular apoptotic death in the hippocampus. The Step-Through is one of the most used behavioral tests to evaluate the memory. When the test is used, it is possible to observe behavioral changes due to loss of memory and learning deficits caused by ischemia. Some studies have been investigating the effect of the exercises in this process and which are the influence on memory and learning. The increase of the blood flow in hippocampus during the exercise is part responsible for the improvement in the ability space learning associated with hipocampal neurogenises. To evaluate the memory, a SHUTTLE BOX with two boxes, a dark one and a light one separated by an automatic door will be used. All groups will be trained in the box, a day before the surgery procedure, for 10 times. After one day of post-initial protocol, the gerbils will be tested at the 2º, 3º, 7º e 12º day in the box. The final test will be applied on the twelfth day. For the motor stimulation, a rodent training treadmill at a fixed speed of 10 m/s, for fifteen minutes will be used. The gerbils will be stimulated twenty-four hours after the injury, doing non-continuous treadmill training for 10 days. For the exercise group, the treadmill training will last 10 uninterrupted days. In this research, eighty-four gerbils, weighing 50 and 70g, will be used, divided into seven groups: Home Cage Group: ingenuous Control Group: ingenuous and without motor stimulation. Control Stimulated Group: ingenuous and stimulated. Sham Group: submitted to experimental surgery without ischemia and without motor stimulation. Stimulated Sham Group: submitted to surgery without ischemia and stimulated. Operated Group: submitted to experimental surgery, without motor stimulation. Stimulated Operated Group: submitted to experimental surgery and stimulated. In the ischemic groups, each animal will be anesthetized and will have the common carotid arteries occluded bilaterally for 5 minutes. In the Sham group, the surgery will be interrupted before the artery occlusion. After the experiments, the anesthetized gerbils and intracardially perfused will be, then, decapitated and their brain dissected, frozen, submitted under histological techniques with Hematoxilin and Eosin. The data will be analyzed by ANOVA and the differences among the groups will be demonstrated by the Dunett´s post-hock test. (AU)