title: Platelet-rich plasma combined with hydroxyapatite for lumbar interbody fusion promoted bone formation and decreased an inflammatory pain neuropeptide in rats.
abstract: METHODS
  A prospective interventional trial, using a rat model of lumbar interbody fusion.
  
  
  OBJECTIVE
  To examine the potential efficacy of platelet-rich plasma (PRP) for lumbar interbody fusion, using hydroxyapatite (HA).
  
  
  BACKGROUND
  PRP is an autologous product containing a high concentration of platelets in a small volume of plasma and has osteoinductive effects. HA has osteoconductive ability and has been used in combination with autogenous bone for spine fusion. However, reports using PRP with HA for spine fusion are very few. The purpose of this study was to examine the efficacy of PRP with HA for spinal interbody fusion and at the same time to estimate the change in immunoreactivity of the inflammatory neuropeptide, calcitonin gene-related peptide (CGRP), in dorsal root ganglion (DRG) neurons innervating spinal discs.
  
  
  METHODS
  A total of 35 Sprague-Dawley rats were used in this study. Twenty-one rats were used for conducting interbody fusion experiments, 7 rats were used as immunostaining controls, and 7 other rats were used as blood donors for making PRP. L5-L6 interbody fusion was performed on 21 rats using HA + PRP (n = 7), HA + platelet-poor plasma (n = 7), or HA + saline (n = 7). Simultaneously, Fluoro-Gold neurotracer was applied to the intervertebral space to detect DRG neurons innervating the discs. L5-L6 lumbar radiographs were obtained and lumbar DRGs were immunostained for CGRP. The rate of bone union and the change in CGRP immunoreactive DRG neurons innervating the discs were evaluated and compared among groups.
  
  
  RESULTS
  All L5-L6 lumbar discs were fused in the PRP + HA group (fused 7/total 7), whereas only 1 case was fused in the platelet-poor plasma group (1 of 7) and no cases in the HA-only group (0 of 7), which was a significant difference. Upon immunohistochemical analysis, CGRP-positive neurons innervated L5-L6 intervertebral discs in nonunion cases, and these were significantly increased compared with those in union cases.
  
  
  CONCLUSIONS
  Our study suggests that using PRP with HA was beneficial for spine fusion. This combination may promote bone union and also decrease inflammatory neuropeptide in sensory neurons innervating the discs.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. kamodahiroto@gmail.com
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kamoda
authors.forename: Masaomi
authors.initials: M
authors.lastname: Yamashita
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyagi
authors.forename: Gen
authors.initials: G
authors.lastname: Arai
authors.forename: Miyako
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yawara
authors.initials: Y
authors.lastname: Eguchi
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sakuma
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Oikawa
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ozawa
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Toyone
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Wada
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D017886:Durapatite / Q000494:pharmacology*; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010976:Platelet Count; D053657:Platelet-Rich Plasma; D011446:Prospective Studies; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D013123:Spinal Fusion / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite; D015740:Calcitonin Gene-Related Peptide