Upregulated Expression of GAP-43 mRNA and Protein in Anterior Horn Motoneurons of the Spinal Cord After Brachial Plexus Injury

Abstract

This study is concerned with the expressions of growth-associated protein-43 (GAP-43) mRNA and protein in the anterior horn of the spinal cord after brachial plexus injury. Animals were killed 1, 7, 14 days after injury and were divided into three injury groups: group 1, right C(7) ventral motor root avulsion; group 2, right C(7) ventral motor root avulsion and cut right C(5)-T(1) dorsal sensitive roots; and group 3, right C(7) ventral motor root avulsion plus right hemisection between C(5) and C(6) segment of the spinal cord. The combined behavioral scores (CBS) 1, 7 and 14 days after surgery were used in behavioral testing. Expressions of both GAP-43 mRNA and protein were analyzed using QRT-PCR and immunohistochemistry 14 days after surgery. Among the injury groups, rats in group 3 had the highest score and those in group 1, the lowest score. On day 14 after surgery, the expressions of GAP-43 mRNA and protein were evidently up-regulated compared to the control group, with the highest in group 3 and the lowest in group 1, showing significant differences among the three injury groups (p <0.01). Our study suggests that the expressions of GAP-43 mRNA and protein may be upregulated after brachial plexus injury, and GAP-43 protein is possibly associated with the axon regeneration and function reconstruction.