Mild-intensity running exercise recovered motor function by improvement of ankle mobility after unilateral brain injury of mice using three-dimensional kinematic analysis techniques

Motor dysfunction, such as gait impairment, is a major disability induced by traumatic brain injury or stroke. Treadmill running is often used as a physical exercise (Ex) clinically and experimentally for the recovery of patients. In animal experiments, although dynamic behavioral deficits can be evaluated using scoring systems, local and minor behaviors are difficult to determine. This study aims to evaluate motor dysfunction and recovery after brain damage (BD) with/without mild-intensity running Ex in mice using three-dimensional (3D) kinematic analysis. To determine exercise intensity, C57/BL6-strain male young adult mice were examined in an incre-mental running test while the pulmonary gas exchange of O2 and CO2 were measured. The animals were then subjected to left hemidecortication as BD, and some mice performed Ex (10 m/min for 30 min 5 times/wk) for 4 weeks. The BD with Ex and BD or sham-operated mice (sham) without (w/o) Ex had their gait recorded by four synchronized cameras, and gait was evaluated via 3D-kinematic analysis. The BD w/o Ex mice significantly differed in stride, step, and stride width for both limbs compared to the sham w/o Ex mice. The BD with Ex mice showed improvement. The BD w/o Ex mice had restricted ankle movements and impairment in dorsal/planter flexing using trajectory analysis. Consistent with these impairments, the nonaffected side also exhibited a different trajectory, suggesting compensatory movements. These results suggest that the appropriate Ex after BD recovered motor function. Furthermore, the present study suggested that 3D-kinematic analysis is a powerful tool for detecting minor behavioral alterations owing to the impairment of the affected side and the compensation of the unaffected side.