GAP-43 expression correlates with spinal motoneuron regeneration following root avulsion.
BACKGROUND
The growth-associated protein GAP-43 plays a crucial role in axonal regeneration in injured neurons.


METHODS
We have used immunohistochemistry to investigate the expression of GAP-43 in spinal motoneurons during nerve reconstruction following root avulsion in the neonatal and adult rats.


RESULTS
Following the injury, GAP-43-immunoreactivity (IR) could be found in adult avulsed motoneurons as early as 1 day, increased from 3 to 7 days and reached a maximal level at 2 weeks post-injury. The up-regulation of GAP-43 in adult avulsed motoneurons was accompanied with the axonal regeneration indicated by numerous regenerating motor axons entering the reimplanted ventral root and nerve. In contrast, GAP-43-IR could not be found in the neonatal avulsed motoneurons at any examined post-injury time points. This failure of up-regulation of GAP-43 was coincident with no axonal regeneration in the reimplanted nerve in the neonatal rats.


CONCLUSIONS
Close association of GAP-43 expression and capacity of regeneration in reimplanted spinal nerve of avulsed motoneurons suggests that GAP-43 is a potential therapeutic target for treatment of root avulsion of brachial plexus.
Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China. qiujuyuan@gmail.com
Qiuju
Q
Yuan
Bing
B
Hu
Huanxing
H
Su
Kwok-Fai
KF
So
Zhixiu
Z
Lin
Wutian
W
Wu