title: Muscle injury in rats induces upregulation of inflammatory cytokines in injured muscle and calcitonin gene-related peptide in dorsal root ganglia innervating the injured muscle.
abstract: In this study we evaluated the relationships among the behavioral changes after muscle injury, histological changes, changes in inflammatory cytokines in the injured muscle, and changes in the sensory nervous system innervating the muscle in rats.
  
  
  
  We established a model of muscle injury in rats using a dropped weight. Behavior was assessed using the CatWalk system. Subsequently, bilateral gastrocnemius muscles and dorsal root ganglia (DRGs) were resected. Muscles were stained with hematoxylin and eosin, and inflammatory cytokines in injured muscles were assayed. DRGs were immunostained for calcitonin gene-related peptide (CGRP).
  
  
  
  Changes of behavior and upregulation of inflammatory cytokines in injured muscles subsided within 2 days of injury. Repaired tissue was observed 3 weeks after injury. However, upregulation of CGRP in DRG neurons continued for 2 weeks after injury.
  
  
  
  These findings may explain in part the pathological mechanism of persistent muscle pain. Muscle Nerve 54: 776-782, 2016.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan. yoshihirosakuma@movie.ocn.ne.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sakuma
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyagi
authors.affiliation: Department of Orthopaedic Surgery, Kitasato University, School of Medicine, Sagamihara, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kamoda
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Oikawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Inage
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Kubota
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sainoh
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis*; D016207:Cytokines / Q000096:biosynthesis*; D005727:Ganglia, Spinal / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000294:innervation / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000502:physiology
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D015740:Calcitonin Gene-Related Peptide
keywords: CatWalk; dropped-weight technique; gait analysis; inflammatory cytokines; muscle injury; muscle pain