Expression of BMP-2 and TGF-beta 1 mRNA during healing of the rabbit mandible.
To identify the cell types which produce BMP and TGF-beta during fracture healing and to elucidate the interactions between BMP and TGF-beta in regulating cell proliferation and differentiation at various stages, an experimental model of fracture healing in the rabbit mandible was established and the expression of BMP-2 and TGF-beta 1 mRNA was studied at different healing stages by in situ hybridization. The results showed that undifferentiated mesenchymal cells, differentiating osteoblasts and chondroblasts, had higher levels of BMP-2 mRNA at the stage of intramembranous bone formation and early chondrogenesis, while the level of TGF-beta 1 mRNA was higher in chondrocytes and active differentiated osteoblasts during chondrogenesis and endochondral ossification, respectively. We conclude that BMP-2 expression was correlated with the differentiation of mesenchymal cells into osteoblasts and chondrocytes. TGF-beta 1 mRNA expression was closely associated with the active synthetic stage of osteoblasts and chondrocytes. These observations suggest that both BMP and TGF-beta are involved in the regulation of fracture healing. BMP may play an important role in bone induction and early chondrogenesis, while TGF-beta regulates the proliferation and active synthetic ability of chondrocytes and osteoblasts.
Si
X
X
Department of Oral Pathology, Stomatological College, Fourth Military Medical University, XI'an, PR China.
Jin
Y
Y
Yang
L
L
Tipoe
G L
GL
White
F H
FH
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000032:analysis / Q000235:genetics*; D002146:Bony Callus / Q000166:cytology / Q000378:metabolism; D002356:Cartilage / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D004195:Disease Models, Animal; D017102:Fracture Healing / Q000235:genetics; D005786:Gene Expression Regulation; D017403:In Situ Hybridization; D008297:Male; D008337:Mandibular Fractures / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D010521:Periosteum / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D011817:Rabbits; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000235:genetics*
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta