Towards a better understanding of bone bridge formation in the growth plate - an immunohistochemical approach.
The growth plate at the end of long bones is the cartilaginous organ responsible for longitudinal bone growth in children. Trauma to the growth plate, i.e. fractures, can severely impair longitudinal bone growth, leading to growth disorders due to destruction of the epiphyseal circulation and formation of a bone bridge. From the clinical experience it is known that in some patients this bone bridge eventually disappears during the growth process. However, the molecular mechanisms involved in bone bridge formation and dissolution have not been clarified yet. The aim of this study was to investigate the spatial and temporal protein level of molecules potentially involved in these processes, i.e. RANKL, OPG, DKK-1, Coll 10, BMP-2 and IL-6, in an experimental rat model using an immunohistochemical approach. The results from our study suggest that bone bridge formation might be an early event starting immediately after growth plate injury and involving several pro-osteoblastic molecules, i.e. IL-6, BMP-2 as well as OPG and Coll X. In the late studied time points 3- and 9-month post-injury expression of anti-osteoblastic proteins, i.e. DKK1 and RANKL, was increased. This indicates that bone bridge dissolution might be a late event and potentially linked to Wnt signaling inhibition and RANK/RANKL signaling activation.
Department of Orthopaedic Surgery, Medical University of Graz , Graz , Austria and.
Karin
K
Pichler
Giuseppe
G
Musumeci
Ines
I
Vielgut
Elisabeth
E
Martinelli
Patrick
P
Sadoghi
Carla
C
Loreto
Annelie-Martina
AM
Weinberg
D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D024121:Collagen Type X / Q000378:metabolism; D006132:Growth Plate / Q000378:metabolism* / Q000473:pathology*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D010012:Osteogenesis; D053244:Osteoprotegerin / Q000378:metabolism; D053245:RANK Ligand / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D055396:Bone Morphogenetic Protein 2; D024121:Collagen Type X; C531384:Dkk1 protein, rat; D036341:Intercellular Signaling Peptides and Proteins; D015850:Interleukin-6; D053244:Osteoprotegerin; D053245:RANK Ligand