Bone induction in intramuscular implants by demineralized bone matrix: sequential changes of collagen synthesis.
Implantation of rat demineralized bone matrix into intramuscular pouches has been shown to cause a complex cellular transition of mesenchymal-type cells into well developed mature bone. Demineralized bone matrix was surgically implanted into rat muscle pouches and removed at various intervals between 7 and 28 days. Histological sections of the implants revealed bone formation by endochondral ossification and appositional bone growth. Biochemical analysis of collagen synthesis demonstrated the following: (1) synthesis of type X collagen, a collagen produced by hypertrophic chondrocytes in the growth plate and in fracture callus. (2) Synthesis of a collagenase-sensitive 17k protein which seems to increase in the early stages of bone induction. Pulse chase analysis indicates that 17k is not a degradation product of another protein and appears to be synthesized without a large Mr precursor. The 17k component contains one or more collagenous domains that are partially resistant to proteolysis with pepsin. Our results confirm the appearance of a cartilage intermediate during demineralized bone matrix induced ossification and implicate the existence of proteins which may be useful markers in future studies on matrix mineralization and ossification.
Guterman
I A
IA
Department of Orthopaedics and Rehabilitation, University of Virginia School of Medicine, Charlottesville 22908.
Boman
T E
TE
Wang
G J
GJ
Balian
G
G
D000818:Animals; D001846:Bone Development; D001857:Bone Matrix / Q000637:transplantation*; D003094:Collagen / Q000096:biosynthesis* / Q000302:isolation & purification; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D003094:Collagen