Osteogenic protein-1 induced gene expression: evaluation in a posterolateral spinal pseudarthrosis model.
METHODS
Molecular study of gene expression in rabbit lumbar pseudarthrosis repairs using reverse transcriptase polymerase chain reaction.


OBJECTIVE
To evaluate differential gene expression of no graft, autograft, and osteogenic protein-1 treated pseudarthroses.


BACKGROUND
Osteogenic protein-1 is a potential bone graft alternative that has achieved high fusion rates in a rabbit lumbar fusion model, including in the repair of nicotine-induced pseudarthroses. A previous study established a correlation between osteogenic protein-1 fusion outcomes and an enhanced level of cytokine gene expression. The expression of such cytokines is known to be decreased in nicotine-exposed rabbit fusion masses.


METHODS
Messenger ribonucleic acid was isolated from nicotine-exposed New Zealand white rabbit lumbar pseudarthroses following attempted no graft, autograft, and osteogenic protein-1 pseudarthrosis repairs. Reverse transcriptase polymerase chain reaction was used to assess the expression of angiogenin, angiopoietin, intercellular adhesion molecule, platelet-derived growth factor-beta, vascular endothelial growth factor, bone morphogenetic proteins 2 and 7, type I collagen, and osteonectin. Glyceraldehyde-3-phosphate dehydrogenase was used as a constitutively expressed control.


RESULTS
Levels of gene expression in the osteogenic protein-1 group were higher than those of the autograft group, which were higher than the no graft group for the majority of the genes studied.


CONCLUSIONS
In the rabbit pseudarthrosis model, gene expression data supported the hypothesis that successful pseudarthrosis repair is related to the induction of osteogenic and angiogenic cytokines by osteogenic protein-1.
White
Andrew P
AP
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
Maak
Travis G
TG
Prince
Daniel
D
Vaccaro
Alexander R
AR
Albert
Todd J
TJ
Hilibrand
Alan S
AS
Grauer
Jonathan N
JN
D000818:Animals; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D008159:Lumbar Vertebrae / Q000378:metabolism* / Q000601:surgery; D011542:Pseudarthrosis / Q000235:genetics / Q000378:metabolism* / Q000601:surgery; D011817:Rabbits; D016103:Spinal Fractures / Q000235:genetics / Q000378:metabolism* / Q000601:surgery; D013123:Spinal Fusion / Q000379:methods; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics
D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta