Effects of treadmill training on microvascular remodeling in the rat after spinal cord injury

Introduction : The morphological characteristics of skeletal muscles innervated caudal to a spinal cord injury (SCI) undergo dramatic phenotypic and microvascular changes. Method : Female Sprague–Dawley rats received a severe contusion at thoracic level 9/10 and were randomly assigned to locomotor training, epidural stimulation, or a combination of the treatment groups (CB). Fiber type composition and capillary distribution were assessed in phenotypically distinct compartments of the tibialis anterior. Results : Spinal cord injury induced a shift in type II fiber phenotype from oxidative to glycolytic (P < 0.05) as well as capillary loss within the oxidative core and glycolytic cortex; the CB treatment best maintained capillary supply within both compartments. Discussion : The angiogenic response of CB training improved capillary distribution across the muscle; capillary distribution became spatially more homogeneous and mean capillary supply area decreased, potentially improving oxygenation. There is an important role for weight‐bearing training in maintaining the oxidative phenotype of muscle after SCI. Muscle Nerve 59 :370–379, 201