Increase of sodium channels (nav 1.8 and nav 1.9) in rat dorsal root ganglion neurons exposed to autologous nucleus pulposus

Kazuyuki Watanabe; Karin Larsson; Björn Rydevik; Shin-Ichi Konno; Claes Nordborg; Kjell Olmarker

doi:10.2174/1874325001408010069

Increase of sodium channels (nav 1.8 and nav 1.9) in rat dorsal root ganglion neurons exposed to autologous nucleus pulposus

Open Orthop J. 2014 Apr 4:8:69-73. doi: 10.2174/1874325001408010069. eCollection 2014.

Authors

Kazuyuki Watanabe¹, Karin Larsson², Björn Rydevik², Shin-Ichi Konno³, Claes Nordborg⁴, Kjell Olmarker⁵

Affiliations

¹ 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.
² Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
³ Department of Orthopaedic Surgery, Fukushima Medical University, School of Medicine, Fukushima, Japan.
⁴ Department of Pathology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁵ Musculoskeletal Research, Department of Medical Chemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

Abstract

Purpose: 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.

Method: 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.

Result: 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.

Conclusion: The findings in the present study demonstrate a neuronal mechanism that may be of importance in the pathophysiology of sciatic pain in disc herniation.

Keywords: DISC herniation; dorsal root ganglion; rat; sciatica; spine; voltage-gated sodium channel..