title: Effects of bisphosphonate on the endochondral bone formation of the mandibular condyle.
abstract: The development of the mandibular condylar cartilage is important for the overall growth of the mandible. However, there have been a few researches into medical approaches aimed at controlling condylar growth. This study examined the effects of bisphosphonate on the growth of the condylar cartilage. Alendronate (3.5 mg/kg/week) was administered to postnatal day 1 SD rats for 7 and 10 days. The thickness of each chondrocyte layer and the level of MMP-9 expression were measured. The anteroposterior diameter of the developing condyle was unaffected by the alendronate treatment for 7 days (P > 0.05). The total thickness of the cartilage layers was also unaffected by the treatment for 7 days (P > 0.05). In particular, there was no change in the thickness of the perichondrium and reserve cell layer at the measured condylar regions (P > 0.05). However, the thickness of the proliferating cell layer was reduced significantly, whereas the thickness of hypertrophied cartilage layer was increased (P < 0.05). The number of chondroclasts engaged in hypertrophied cartilage resorption was reduced significantly by the alendronate treatment (P < 0.05). The level of MMP-9 expression was reduced at both the transcription and translation levels by the alendronate treatment for 7 and 10 days. These results indicate that alendronate (>3.5 mg/kg/week) inhibits the longitudinal growth of the mandibular condyle by inhibiting chondrocyte proliferation and the resorption of hypertrophied cartilage for ossification.
authors.affiliation: Dental Science Research Institute, 2nd stage Brain Korea, School of Dentistry, Chonnam National University, Gwangju, South Korea.
authors.forename: M S
authors.initials: MS
authors.lastname: Kim
authors.forename: S Y
authors.initials: SY
authors.lastname: Jung
authors.forename: J H
authors.initials: JH
authors.lastname: Kang
authors.forename: H J
authors.initials: HJ
authors.lastname: Kim
authors.forename: H M
authors.initials: HM
authors.lastname: Ko
authors.forename: J Y
authors.initials: JY
authors.lastname: Jung
authors.forename: J T
authors.initials: JT
authors.lastname: Koh
authors.forename: W J
authors.initials: WJ
authors.lastname: Kim
authors.forename: S M
authors.initials: SM
authors.lastname: Kim
authors.forename: E J
authors.initials: EJ
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D019386:Alendronate / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001846:Bone Development / Q000187:drug effects*; D002358:Cartilage, Articular / Q000166:cytology; D004334:Drug Administration Schedule; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D008335:Mandibular Condyle / Q000187:drug effects* / Q000502:physiology; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D050071:Bone Density Conservation Agents; D020780:Matrix Metalloproteinase 9; D019386:Alendronate