title: The effect of irradiation and hyperbaric oxygenation (HBO) on extracellular matrix of the condylar cartilage after mandibular distraction osteogenesis in the rabbit.
abstract: The effects of irradiation and hyperbaric oxygenation (HBO) on the extracellular matrix of condylar cartilage after mandibular distraction were evaluated. Unilateral distraction was performed on 19 rabbits. Five study groups were included: control, low- and high-dose irradiation, and low- and high-dose irradiation groups with HBO. Additionally, four temporomandibular joints (TMJ) were used as control material. The high-dose irradiated animals were given in the TMJ 22.4 Gy/4 fractions irradiation (equivalent to 50 Gy/25 fractions). Low-dose irradiation group received a 2.2 Gy dosage. Two groups were also given preoperatively HBO 18 x 2.5ATA x 90 min. After a two-week distraction period (14 mm lengthening) and four-week consolidation period the TMJs were removed. Proteoglycan (PG) distribution of the extracellular matrix was evaluated using safranin O staining and collagen I and II using immunohistochemistry. The organization of fibrillar network was studied by polarized light microscopy. On the operated side of the control group and on the unoperated side in all, except for high-dose irradiated group, PG distribution and fibrillar network were normal appearing. In the irradiated groups, with or without HBO, the cartilaginous layer was partially or totally devoid of PG and the network structure was severely damaged. In conclusion, irradiation in conjunction with the pressure applied by distraction causes severe damage to extracellular matrix of condylar cartilage.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Turku, Lemminkäisenkatu 2, 20520 Turku, Finland. arja.muhonen@kolumbus.fi
authors.forename: A
authors.initials: A
authors.lastname: Muhonen
authors.forename: A-M
authors.initials: AM
authors.lastname: Säämänen
authors.forename: T
authors.initials: T
authors.lastname: Peltomäki
authors.forename: R-P
authors.initials: RP
authors.lastname: Happonen
mesh_terms: D000818:Animals; D002356:Cartilage / Q000473:pathology / Q000528:radiation effects*; D024042:Collagen Type I / Q000032:analysis / Q000528:radiation effects; D024043:Collagen Type II / Q000032:analysis / Q000528:radiation effects; D004396:Coloring Agents; D005109:Extracellular Matrix / Q000473:pathology / Q000528:radiation effects*; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000528:radiation effects; D024022:Fibrillar Collagens / Q000528:radiation effects / Q000648:ultrastructure; D006931:Hyperbaric Oxygenation; D008334:Mandible / Q000601:surgery*; D008335:Mandibular Condyle / Q000473:pathology / Q000528:radiation effects*; D019857:Osteogenesis, Distraction / Q000295:instrumentation; D010315:Particle Accelerators; D010619:Phenazines; D011509:Proteoglycans / Q000032:analysis / Q000528:radiation effects; D011817:Rabbits; D011829:Radiation Dosage; D013704:Temporomandibular Joint / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II; D004396:Coloring Agents; D016326:Extracellular Matrix Proteins; D024022:Fibrillar Collagens; D010619:Phenazines; D011509:Proteoglycans; C009195:safranine T