Wheel-Running Modestly Promotes Functional Recovery after a Unilateral Cortical Lesion in Rats

Background: We aimed to determine whether early or delayed wheel-running (W) after a cortical lesion in rats influences functional recovery and protein expression involving synaptic plasticity. Methods: 57 rats were arranged in 4 groups: (1) Sham, (2) NMDA, (3) W-24 h or (4) W-72 h (W-24 h and W-72 h means wheel-running for 14 days starting day 1 or day 3 after NMDA lesion). NMDA produced a standardized lesion in the unilateral sensorimotor cortex and detectable behavioral deficits. Synaptogenesis was measured by immunohistochemistry. Results: Wheel-running starting after 24 h had no detectable effect, but it significantly speeded functional recovery when delayed to after 72 h. These results were in accordance with a marker linked to synaptogenesis. Conclusion: Wheel-running starting 3 days, but not 1 day, after an NMDA lesion is associated with improved functional recovery.