title: Changes in the Expressions of Iba1 and Calcitonin Gene-Related Peptide in Adjacent Lumbar Spinal Segments after Lumbar Disc Herniation in a Rat Model.
abstract: Lumbar disc herniation is commonly encountered in clinical practice and can induce sciatica due to mechanical and/or chemical irritation and the release of proinflammatory cytokines. However, symptoms are not confined to the affected spinal cord segment. The purpose of this study was to determine whether multisegmental molecular changes exist between adjacent lumbar spinal segments using a rat model of lumbar disc herniation. Twenty-nine male Sprague-Dawley rats were randomly assigned to either a sham-operated group (n=10) or a nucleus pulposus (NP)-exposed group (n=19). Rats in the NP-exposed group were further subdivided into a significant pain subgroup (n=12) and a no significant pain subgroup (n=7) using mechanical pain thresholds determined von Frey filaments. Immunohistochemical stainings of microglia (ionized calcium-binding adapter molecule 1; Iba1), astrocytes (glial fibrillary acidic protein; GFAP), calcitonin gene-related peptide (CGRP), and transient receptor potential vanilloid 1 (TRPV1) was performed in spinal dorsal horns and dorsal root ganglions (DRGs) at 10 days after surgery. It was found immunoreactivity for Iba1-positive microglia was higher in the L5 (P=0.004) dorsal horn and in the ipsilateral L4 (P=0.009), L6 (P=0.002), and S1 (P=0.002) dorsal horns in the NP-exposed group than in the sham-operated group. The expression of CGRP was also significantly higher in ipsilateral L3, L4, L6, and S1 segments and in L5 DRGs at 10 days after surgery in the NP-exposed group than in the sham-operated group (P<0.001). Our results indicate that lumbar disc herniation upregulates microglial activity and CGRP expression in many adjacent and ipsilateral lumbar spinal segments.
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Daegu Catholic University, Daegu, Korea.
authors.forename: Hee Kyung
authors.identifier: 0000-0003-1950-9926
authors.initials: HK
authors.lastname: Cho
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Korea. ; Medical Devices Clinical Trial Center, Yeungnam University, Daegu, Korea.
authors.forename: Sang Ho
authors.identifier: 0000-0003-2921-7820
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: Medical Devices Clinical Trial Center, Yeungnam University, Daegu, Korea.
authors.forename: So-Yeon
authors.identifier: 0000-0003-1794-3446
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Medical Devices Clinical Trial Center, Yeungnam University, Daegu, Korea.
authors.forename: Mi-Jung
authors.identifier: 0000-0002-2283-5821
authors.initials: MJ
authors.lastname: Choi
authors.affiliation: Department of Anatomy and Cell Biology, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Se Jin
authors.identifier: 0000-0002-8031-9980
authors.initials: SJ
authors.lastname: Hwang
authors.affiliation: Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Korea.
authors.forename: Yun Woo
authors.identifier: 0000-0002-6585-327X
authors.initials: YW
authors.lastname: Cho
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D004195:Disease Models, Animal; D005727:Ganglia, Spinal / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007405:Intervertebral Disc Displacement / Q000378:metabolism*; D008159:Lumbar Vertebrae / Q000378:metabolism*; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism*; D017628:Microglia / Q000378:metabolism; D009437:Neuralgia / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D066148:Spinal Cord Dorsal Horn / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C100745:Aif1 protein, rat; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins; D015740:Calcitonin Gene-Related Peptide
keywords: Calcitonin Gene-Related Peptide; Lumbar Disc Herniation; Microglia; Multisegmental; Neural Pathways; Neuropathic Pain