Increase of sodium channels (nav 1.8 and nav 1.9) in rat dorsal root ganglion neurons exposed to autologous nucleus pulposus.
OBJECTIVE
It has been assumed that nucleus pulposus-induced activation of the dorsal root ganglion (DRG) may be related to an activation of sodium channels in the DRG neurons. In this study we assessed the expression of Nav 1.8 and Nav 1.9 following disc puncture.


METHODS
Thirty female Sprague-Dawley rats were used. The L4/L5 disc was punctured by a needle (n=12) and compared to a sham group without disc puncture (n=12) and a naive group (n=6). At day 1 and 7, sections of the left L4 DRG were immunostained with anti-Nav 1.8 and Nav 1.9 antibodies.


RESULTS
At day 1 after surgery, both Nav 1.8-IR neurons and Nav 1.9-IR neurons were significantly increased in the disc puncture group compared to the sham and naive groups (p<0.05), but not at day 7.


CONCLUSIONS
The findings in the present study demonstrate a neuronal mechanism that may be of importance in the pathophysiology of sciatic pain in disc herniation.
Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden ; Department of Orthopaedic Surgery, Fukushima Medical University, School of Medicine, Fukushima, Japan.
Kazuyuki
K
Watanabe
Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Karin
K
Larsson
Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Björn
B
Rydevik
Department of Orthopaedic Surgery, Fukushima Medical University, School of Medicine, Fukushima, Japan.
Shin-Ichi
S
Konno
Department of Pathology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Claes
C
Nordborg
Musculoskeletal Research, Department of Medical Chemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Kjell
K
Olmarker
DISC herniation; dorsal root ganglion; rat; sciatica; spine; voltage-gated sodium channel.