Development of a larger animal model of spinal cord inury for teh establishment of effective clincal therapy

Abstract

In case of development of an effective clinical therapy , it is necessary to establish a model in animals larger than laboratory animals as a pre-clinical assessment. And conventional contusion models required preinjury laminectomy to expose the cord, which changes the condition surrounding the spinal cord. Then, we developed a new SCI model in dogs that uses a balloon and no laminectomy. A balloon catheter was inserted via the intervertebral foramen, into the extradural space in 7 dogs. The balloon was inflated at the L1 level by injection of saline. After 4 h of surgery, a region of high intensity was observed with MR imaging. Basso, Beattie and Bresnahan (BBB) scores of models in which compression was achieved by inflation of the balloon with 1.5 ml saline remained at zero for 6 months after surgery. During electrophysiological studies performed by magnetic stimulation, no hindlimb movement was observed on stimulation beyond the area of contusion. Pathological examination showed the formations of cavities surrounded by scar tissue and that these scarred areas contained high levels of collagen. These findings closely resembled those of clinical cases.In our clinical experience on the recovery of injured peripheral nerves, we realized the importance of the local biological condition for the regeneration. Using this SCI model we are now attempting to several trials and the latest results are presented in this symposium. [Jpn J Physiol 54 Suppl:S22 (2004)]