title: Innervation of the sacroiliac joint in rats by calcitonin gene-related peptide-immunoreactive nerve fibers and dorsal root ganglion neurons.
abstract: The sacroiliac joint (SIJ) can be a source of low back pain. Calcitonin gene-related peptide (CGRP) has been reported to play a significant role in nociceptive processing. However, the occurrence of CGRP-immunoreactive (CGRP-ir) sensory nerve fibers in the SIJ has not been fully defined. The present study investigated CGRP-ir nerve fibers supplying the SIJ. CGRP-ir nerve fibers in the vicinity of the SIJ cartilage and CGRP-ir neurons in the bilateral dorsal root ganglia (DRG) were examined immunohistochemically by administering anti-CGRP antiserum to rats. The SIJ was decalcified and cut into sections, and the CGRP-ir fibers around the SIJ cartilage were counted under microscopy. In another group, fluoro-gold (F-G), a neural tracer, was injected into the SIJ from the dorsal or ventral side with dorsal or ventral denervation. The number of F-G-labeled CGRP-ir neurons was counted in individual DRG. CGRP-ir fibers were observed more frequently in the tissues adjacent to the cranial part of the SIJ surface. In the case of dorsal denervation (ventral nerve supply), the CGRP-ir neurons composed 18.2% of the F-G-labeled neurons. In the case of ventral denervation (dorsal nerve supply), the CGRP-ir neurons composed 40.9% of the F-G-labeled neurons. There was a statistically significant difference in the number of CGRP-ir neurons between the ventral and dorsal nerve supplies to the SIJ. The cranial part of the dorsal side could be the part most associated with pain in the SIJ.
authors.affiliation: Department of Orthopaedic Surgery, Shimoshizu National Hospital, Chiba, Japan. yasuaki.murata@me.point.ne.jp
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Murata
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
authors.forename: Hideshige
authors.initials: H
authors.lastname: Moriya
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000276:immunology*; D005727:Ganglia, Spinal / Q000033:anatomy & histology* / Q000166:cytology; D008297:Male; D009412:Nerve Fibers / Q000276:immunology*; D009474:Neurons / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012446:Sacroiliac Joint / Q000276:immunology / Q000294:innervation*
chemical_list: D015740:Calcitonin Gene-Related Peptide