Continuous and not continuous 2-week treadmill training enhances the performance in the passive avoidance test in ischemic gerbils

This study aims to investigate the frequency and total duration effects of the 2-week treadmill training after experimental ischemic stroke in the passive avoidance test. We performed bilateral occlusion of common external carotid arteries, for five minutes, in Mongolian gerbils. The training groups were: continuous training for twelve consecutive days or not continuous training for six non-consecutive days. The groups remained in the treadmill for 15 min, with the speed set at 10 m/min, and the training started 24 h after the stroke. In the Shuttle Box, each animal had ten trials during the Learning Session (LS), which occurred 24 h before the stroke. The Retention Test (RT) occurred 24 h after the stroke and started on the second, third, seventh and twelfth day after LS. After the experiments, the brains were perfused, and coronal sections of the CA1 area of the hippocampus were cut and stained with hematoxylin and eosin. ANOVA on Ranks was used for Behavioral data analysis and morphological data by percentage. Ischemic training groups showed preservation in neuron density in the CA1 area of the hippocampus, when compared to the control groups. Animals subjected to continuous training, showed a higher latency in the RT when compared to ischemic animals in both weeks [(2nd, H = 39.81; P < 0.05), (3rd, H = 38.08; P < 0.05), (7th, H = 44.17; P < 0.05), and (12th, H = 39.55; P < 0.05). Animals in the not continuous training showed higher latency in the RT, in the second week only [(2nd, H = 39.81; P < 0.05), (3rd, H = 38.08; P < 0.05), (7th, H = 44.17; P < 0.05), and (12th, H = 39.55; P < 0.05). These findings suggest that improvement of memory after stroke after treadmill training is dependent on the frequency and total duration of training.