Gene expression of TGF-β superfamily during healing of bone fracture

Research Project

Project/Area Number	12671784
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Morphological basic dentistry
Research Institution	Nihon-University
Principal Investigator	ISHII Teruhiko Nihon-University, School of Dentistry, Research Assistant, 歯学部, 助手 (40267092)
Co-Investigator(Kenkyū-buntansha)	HORI Minoru Nihon-University, School of Dentistry, Associate Prof., 歯学部, 講師 (60096899) INAGA Toshihiko Nihon-University, School of Dentistry, Associate Prof., 歯学部, 助教授 (90096769)
Project Period (FY)	2000 – 2001
Project Status	Completed (Fiscal Year 2001)
Budget Amount *help	¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	bone fracture / BMP / BMP receptor / osteoclast / osteoblast / autocrine / aracreine / レセプター / paracreine / TGF-β super family / ISH / 遺伝子発現 / 骨折治癒過程
Research Abstract	BMPs play a fundamental role in bone regeneration. Localization of BMP and BMPR (BMP receptor) was investigated during healing of mandibular fractures in rats. The immunoreactivities of BMP and receptors showed the same distributions. The immunoreactions were observed in fibroblast-like cells in bone fissures with blood clots and connective tissue cells in muscular tissue from 1 to 2 days after the bone fracture. Fibrosis was found from 3 days, and intense immunoreactions were found in the fibroblasts. Cartilage formation started from 4 days, and the immunoreactions were found in the chondroblasts, proliferative and resting chondrocytes, but not in hypertrophic chondrocytes. Bone resorption in osteoclasts was observed in the region of the bone fracture, and intense immunoreactions were found in the osteoclasts. Bone formation was observed from 7 days and cartilage was gradually replaced by bone. Intense immunoreactions were found in osteoblasts along newly formed bone trabeculae. Immunoreactions of osteoblasts were gradually decreased after 14 days, and they were not found at 28 days. The immunohistochemical localization of BMPR-IB showed the same distribution patterns as those with BMPR-IA and II. These results suggest that BMPs play a central role in cartilage and bone formation during healing of bone fractures, particularly in bone resorption by osteoclasts.