Functional and Physiological Effects of Treadmill Training Induced by Buspirone, Carbidopa, and L-DOPA in Clenbuterol-Treated Paraplegic Mice

Background. Chronic spinal cord injury may be complicated by weight loss, muscle atrophy, and bone loss. Objective. The authors identified a combination pharmacotherapy using buspirone, carbidopa, and L-DOPA (BCD) that elicits bouts of locomotor-like movements in spinal cord–transected (Tx) mice. They then evaluated the effects of 8 weeks of treadmill training in Tx mice that received BCD or BCD + clenbuterol, a monoaminergic agent with anabolic properties, on locomotor function, muscle atrophy, adipose tissue loss, and bone density measures. Methods. Induced locomotor movement, adipose tissue, skeletal muscle, and femoral bone properties were compared in unoperated control mice, operated controls (untreated, untrained Tx mice), and 2 groups of treated, trained Tx mice (Tx + BCD, Tx + BCD + clenbuterol) that also received training. Results. BCD- and BCD + clenbuterol–treated mice showed comparable levels of locomotor movements that significantly improved over time. Soleus muscle mass and soleus and extensor digitorum longus cross-sectional area significantly increased in both groups of BCD-treated mice, with greater effects in BCD + clenbuterol–treated animals. Fiber type conversion, adipose tissues, bone mineral density, and content were reduced in all Tx groups compared with unoperated control mice. Conclusion. These findings suggest that locomotor movement and muscle properties can be restored to near-normal levels after several weeks of BCD treatment, regular training, and clenbuterol in completely paraplegic animals.