Functional roles of intrinsic neurotrophin-3 in spinal neuroplasticity of cats following partial ganglionectomy

Abstract

This study detected the effects of endogenous neurotrophin-3 (NT-3) on the collateral sprouting derived from the L6 dorsal root ganglion (DRG) after unilateral removal of adjacent DRGs (L1–L5 and L7) in cats. Cholera toxin B tracing revealed significant neurite growth from the spared L6 DRG and axonal sprouting in the dorsal column. There was a significant increase in the number of NT-3 and trkC immunopositive neurons as well as in NT-3 protein level in the spared DRG by immunohistochemistry and enzyme-linked immunoadsorbent assay. NT-3 and its mRNA and trkC were located mainly in large- and medium-sized DRG neurons. NT-3 antibody neutralization in vivo and in vitro results in marked reduction in sprouted fibers. These findings point to an important role of NT-3 in neural plasticity at dorsal column axons.

Keywords::

• NT-3
• trkC
• dorsal root ganglion
• in situ hybridization
• plasticity

Acknowledgments

This research was supported by a grant from the New York–China Medical Board (CMB00-722). We sincerely thank Professors Seng-Kee Leong and Wei-Yi Ong for their insightful comments and revision of the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.