Clenbuterol, a beta2-adrenoceptor agonist, reduces scoliosis due to partial transection of rat spinal cord.

Abstract

Injury to the spinal cord often results in abnormal lateral curvature of the spine, or scoliosis, that is associated with neuromuscular weakness. The lateral curvature of the spine is thought to be a consequence of insufficient or asymmetrical loading of the vertebrae. To study neuromuscular scoliosis, an animal model of spinal cord injury was used in which the spinal cord was partially (3/4) transected, with the left lateral columns left intact. Partial transection of the spinal cord in the rat caused scoliosis that was maximal four to five vertebrae distal to the lesion site. As in previous experiments involving unilateral spinal cord lesions, the scoliotic curves were convex on the weakened side. Subtotal transection at T5 or T11 resulted in lateral displacement of vertebrae T9-T12 or L2-L5, respectively, of up to 11 mm. Interestingly, this vertebral displacement is greatly reduced by clenbuterol, a beta2-adrenoceptor agonist that has been found to retard loss of muscle contractility and bone mineralization due to denervation. Together these results suggest that stimulation of beta2-receptors opposes vertebral unloading due to neuromuscular weakness and thereby acts as a countermeasure to scoliosis.