Upregulated expression of GAP-43 mRNA and protein in anterior horn motoneurons of the spinal cord after brachial plexus injury

Abstract

Background and Aims: 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. Methods: 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. Results: 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). Conclusions: 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. © 2010 IMSS.