Abstract
Objectives
To evaluate the feasibility of achieving bone formation by percutaneous gene delivery, with plasmid DNA encoding BMP- 7(OP- 1).
Summary of Literature Review
Currently, the preferred method for posterolateral spinal fusion involves decortication of the transverse process, followed by a graft of autogenous bone harvested from the iliac crest. Unfortunately, this procedure suffers from significant morbidity, including blood loss, infection and persistent pain at the harvest site.
Material and Methods
24 Sprague- Dawley rats, weighing approximately 250∼300 g, were used. The percutaneous injection was attempted above both the L5 transverse processes.
The animals were divided into three groups, according to the injection materials: 1) OP- 1 gene/collagen, 2) recombinant OP- 1 protein/collagen and 3) control of PBS/collagen. A t 2 and 4 weeks post- injection, the animals were sacrificed. The gross, radiological and histological findings were analyzed.
Results
No bone was detected grossly by manual palpation or radiography in the groups receiving OP- 1 gene/collagen at either time point. The histological findings revealed the initiation of endochondral bone formation within the paraspinal muscle, directly above the L5 transverse process.
In the rhOP- 1 protein/collagen groups, the gross, radiological and histological findings revealed extensive cartilage and bone formation at both 2 and 4 weeks.
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