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

Background and AimsThis 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.MethodsAnimals were killed 1, 7, 14 days after injury and were divided into three injury groups: group 1, right C7 ventral motor root avulsion; group 2, right C7 ventral motor root avulsion and cut right C5-T1 dorsal sensitive roots; and group 3, right C7 ventral motor root avulsion plus right hemisection between C5 and C6 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.ResultsAmong 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).ConclusionsOur 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.