title: Involvement of sensory neurons in bone defect repair in rats.
abstract: We investigated bone repair in sensory-denervated rats, compared with controls, to elucidate the involvement of sensory neurons. Nine-week-old male Wistar rats received subcutaneous injections of capsaicin to denervate sensory neurons. Rats treated with the same amount of vehicle served as controls. A standardized bone defect was created on the parietal bone. We measured the amount of repaired bone with quantitative radiographic analysis and the mRNA expressions of osteocalcin and cathepsin K with real-time polymerase chain reaction (PCR). Quantitative radiographic analysis showed that the standard deviations and coefficients of variation for the amount of repaired bone were much higher in the capsaicin-treated group than in the control group at any time point, which means that larger individual differences in the amount of repaired bone were found in capsaicin-treated rats than controls. Furthermore, radiographs showed radiolucency in pre-existing bone surrounding the standardized defect only in the capsaicin-treated group, and histological observation demonstrated some multinuclear cells corresponding to the radiolucent area. Real-time PCR indicated that there was no significant difference in the mRNA expression levels of osteocalcin and cathepsin K between the control group and the capsaicin-treated group. These results suggest that capsaicin-induced sensory denervation affects the bone defect repair.
authors.affiliation: Division of Oral Surgery, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Henmi
authors.forename: Megumi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Seishi
authors.initials: S
authors.lastname: Echigo
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Sasano
mesh_terms: D000818:Animals; D015415:Biomarkers; D001861:Bone Regeneration; D002211:Capsaicin / Q000008:administration & dosage; D056657:Cathepsin K / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007279:Injections, Subcutaneous; D008297:Male; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism / Q000473:pathology; D010294:Parietal Bone / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000293:injuries* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D011984:Sensory Receptor Cells / Q000187:drug effects* / Q000473:pathology
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D015675:Osteocalcin; D056657:Cathepsin K; D002211:Capsaicin