The Changes Of GAP-43 And CGRP Expression In The Spinal Cord After The Spinal Cord Injured In Rats.

Objective Establishing cryogenic spinal cord injury rat model,in order to observe the changes of GAP-43 and CGRP expression in the spinal cord,and study the primary mechanism on the spinal cord injury.It will provide theoretical evidence for the experimentally therapy of the impaired spinal cord.Methods Sixty adult Sprague-Dawley rats were randomly divided into normal group,sham-operated group and the spinal cord injury group.In the experiment group,after the T9-T11 spinous process and the corresponding vertebral lamina were removed,the spinal cord of T10 segment was freezed by liquid nitrogen.In sham-operated group,rats received only T10 laminectomies. In normal group,rats not received opreration.The normal group and sham-operated group rats were killed at 14d after operation.The experimental group rats were killed at 2h,6h,12h,24h,48h,3d,7d and 14d after operation according to the survival time.The expression of GAP-43 and CGRP in the spinal cord detected by immunohistochemical staining and image analysis methods.Results The hindered walking and equilibrium function were evident to show that the cryogenic spinal cord injury rats model is successeful.The expression of GAP-43 in the uninjured spinal cord was lower.But the expression of GAP-43 was increased in the spinal cord after the spinal cord was freezed by liquid nitrogen.The expression of GAP-43 in the spinal cord after injury was increased at day 3,and further increased to the highest expression at day 7,but the expression of GAP-43 was reduced quickly atday 14.The expression of CGRP in the uninjured spinal cord was high.But the expression of GAP-43 in the spinal cord after injury decreased at day 3,and further reduced at day 7 and 14.Conclusion The cryogenic spinal cord injury rat model is a stable and reliable spinal cord injury animal model.The expression of GAP-43 and CGRP were changed in the spinal cord after the spinal cord injured in rats.It suggested that GAP-43 and CGRP may participate in the process of degeneration and regeneration after nerve injury and promote nerve regeneration.But the primary mechanism on the recovery of spinal cord injury need to study in future.