Aoki, Yasuchika MD, PhD; An, Howard S. MD; Takahashi, Kazuhisa MD, PhD Miyamoto, Kei MD, PhD; Lenz, Mary Ellen MS; Moriya, Hideshige MD, PhD; Masuda, Koichi MD
Nerve ingrowth into the disc is recognized to be one of the causes of discogenic pain. Almost all of these disc-innervating neurons are NGF-sensitive. The axonal growth potential of NGF-sensitive neurons has not been investigated. The objective of this study was to examine the effects of neuronal injury and tumor necrosis factor-[alpha] (TNF-[alpha]) on the axonal growth potential of 2 types of nociceptive DRG neurons: nerve growth factor (NGF)-sensitive and glial cell line-derived neurotrophic factor (GDNF)-sensitive neurons. The authors conclude that the results suggest that the cultured DRG neurons exhibit pathologic changes similar to those found in injured neurons. NGF-sensitive neurons, which include disc-innervating neurons, may have a greater potential to extend their axons in response to neuronal injury under pathologic conditions in the presence of TNF-[alpha] than GDNF-sensitive neurons.
Spine. 32(8):857-863, April 15, 2007.