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A gene therapy approach to accelerating bone healing Evaluation of gene expression in a New Zealand white rabbit model

Evaluation of gene expression in a New Zealand white rabbit model
  • A. W. A. Baltzer
  • Christian Lattermann
  • J. D. Whalen
  • Stefan Braunstein
  • Paul D. Robbins
  • Christopher H. Evans
Experimental Study

Abstract

It has been demonstrated that BMPs, IGFs, and TGFβs improve the process of bone healing in vivo. We have suggested the use of gene therapy as a possible way to deliver growth factors to fracture sites in order to improve repair. The aim of this study was to develop a minimally invasive gene therapy approach to treat bone injuries locally without damaging the local blood circulation. A segmental defect of 1.3 cm was created in the diaphysis of the femur in mature NZW rabbits. Internal fixation with 7-hole DCP plates and 2.7 mm screws was used to stabilize the bone. After building a chamber by tightly closing the muscles around the segmental defect, 0.5 ml of either saline solution or a collagen gel containing 1 × 1010 particles of adenovirus carrying cDNA encoding either the bacterial β-galactosidase gene (LacZ), or the firefly luciferase gene were injected into the gap. The control side received 0.5 ml of saline solution without virus particles. Bone marrow, cortical and trabecular bone and surrounding muscle were harvested from the injected femur and were analyzed for local gene expression through X-gal staining or measurement of local luciferase activity. To determine whether distant sites were transduced, tissue from the spleen, liver, and lung were harvested as well as bone, bone marrow and muscle from the contralateral diaphysis of the femur. The delivery of the adenoviral vector suspended in saline solution led to local transduction of the bone, bone marrow and the muscle surrounding the gap. No luciferase activity was found in the contralateral femur, lung, or spleen, and only transient luciferase activity was seen in the liver. While marker gene expression persisted within the surrounding soft tissues for at least 2 weeks, the expression in bone lasted up to 6 weeks. This study has shown that it is possible to use adenoviral vectors to transfer and express genes locally within a segmental defect. Gene expression persisted for several weeks, which may be already sufficient to accelerate repair.

Key words Gene therapy Fracture healing Femoral defect model Rabbit 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • A. W. A. Baltzer
    • 1
  • Christian Lattermann
    • 2
  • J. D. Whalen
    • 2
  • Stefan Braunstein
    • 3
  • Paul D. Robbins
    • 4
  • Christopher H. Evans
    • 2
  1. 1.Orthopädische Universitätsklinik, Heinrich-Heine-Universität, Moorenstrasse 5, D-40225 Düsseldorf, Germany e-mail: baltzer@med.uni-duesseldorf.de Tel.: +49-211-811-6691 Fax: +49-211-811-6691DE
  2. 2.Department of Orthopaedic Surgery, Ferguson Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USAUS
  3. 3.Institut für Pathologie, Heinrich-Heine-Universität, Moorenstrasse 5, D-40225 Düsseldorf, GermanyDE
  4. 4.Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USAUS

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