Early treadmill training promotes motor function after hemorrhagic stroke in rats

Abstract

Rehabilitation after a stroke is very important because it has beneficial effects on brain function, including the promotion of plasticity. However, an optimal time window for rehabilitation interventions after hemorrhagic stroke has not been clearly defined. The aim of this study was to determine whether early exercise training initiated 24h after an intracerebral hemorrhage (ICH) might enhance neurologic recovery more than exercise initiated 1 week after ICH without hematoma expansion and edema volume increase. We subjected adult male Sprague-Dawley rats to experimental ICH by the intrastriatal administration of bacterial collagenase. The rats were randomly divided into the following 2 groups: early training group (treadmill exercise started 24h post-ICH; n=18) and late training group (treadmill exercise started 1-week post-ICH; n=18). Two weeks after surgery we performed neurologic tests (rota-rod, modified limb-placing, and adhesive-dot removal tests), and measured hematoma volumes and brain water content. In the late training group, compared with the pre-ICH performance on the rota-rod test (98.3+/-69.4s), the animals had significantly worse performance after the post-ICH rehabilitation (40.5+/-52.6s; p<0.01, paired t-test). In the early training group however, the motor performance after the post-ICH rehabilitation (56.4+/-73.5s) was not significantly different from the baseline pre-ICH performance (79.8+/-33.9s; p=0.24). There were no significant differences between the two groups with respect to the other neurologic tests. Early exercise did not increase hematoma size or brain water content. Early treadmill training could be performed safely, and enhanced motor recovery in a rat model of ICH. Further studies are required to translate the results into clinical significance.