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Wheel running following spinal cord injury improves locomotor recovery and stimulates serotonergic fiber growth
Author(s) -
EngesserCesar Christie,
Ichiyama Ronaldo M.,
Nefas Amber L.,
Hill Mary Ann,
Edgerton V. Reggie,
Cotman Carl W.,
Anderson Aileen J.
Publication year - 2007
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2007.05469.x
Subject(s) - spinal cord injury , serotonergic , treadmill , medicine , physical medicine and rehabilitation , spinal cord , serotonin , physical therapy , receptor , psychiatry
Exercise, through manual step training, robotic step training or voluntary wheel running, is emerging as a promising therapy after spinal cord injury (SCI). Animal models provide a tool to investigate the mechanisms by which physical activity influences recovery from SCI. In the present study, we extend previous experiments showing improved recovery after SCI with both pre‐ and post‐injury running in a flat‐surface running wheel and investigate mechanisms of recovery. We tested a clinically relevant model using post‐injury wheel running, in which we provided mice with access to wheels either 3 days or 7 days/week. Open field behavior, observed for 15 weeks following moderate T9 contusion injury, showed a significant linear increase in locomotor improvements across groups, sedentary, 3‐day runners and 7‐day runners. Kinematic analysis of treadmill walking revealed that both wheel‐running groups, 3 and 7 days/week, improved stepping ability compared with sedentary controls. Stereological quantification of neuron number in the injured segment of the spinal cord revealed no differences between the groups. However, stereological quantification of serotonin immunostaining using isotropic virtual planes showed increases in serotonin fiber length caudal to the lesion in the running groups. These observations suggest that improvement in function may be related to changes in serotonin fibers immediately caudal to the injury epicenter.