Article
Analysis of the fracture hematoma in the early stage of bone healing by microdialysis
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Authors
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W. Gao
- Universitätsklinikum Carl Gustav Carus, Klinik für Unfall- und Wiederherstellungschirurgie, Dresden, Germany
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Y. Förster
- Universitätsklinikum Carl Gustav Carus, Klinik für Unfall- und Wiederherstellungschirurgie, Dresden, Germany
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C. Rentsch
- Universitätsklinikum Carl Gustav Carus, Klinik für Unfall- und Wiederherstellungschirurgie, Dresden, Germany
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S. Kalkhof
- Helmholtz-Zentrum für Umweltforschung, Department Proteomik, Leipzig, Germany
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H. Zwipp
- Universitätsklinikum Carl Gustav Carus, Klinik für Unfall- und Wiederherstellungschirurgie, Dresden, Germany
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S. Rammelt
- Universitätsklinikum Carl Gustav Carus, Klinik für Unfall- und Wiederherstellungschirurgie, Dresden, Germany
| Published: | October 18, 2011 |
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Outline
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Questionnaire: The different strategies of tissue engineering for functional reconstruction of critical size bone defects require a thorough knowledge of the physiologic mechanisms of bone repair. Several investigations have studied the gene expression one to three days after an acute or experimental fracture. Few is known about the humoral and cellular in vivo reactions in the early phase of bone healing. The aim of this study is to directly detect the mediators, growth factors and components of the extracellular matrix which occur in the first 24 hours within an experimental bone defect by microdialysis.
Methods: A 6 mm defect was created in the right femur of adult male Wistar rats and stabilized by plate osteosynthesis. A control group had only sham surgery. A microdialysis catheter (cut-off 100kDa) was placed within the defect and the samples were collected continuously for up to 24 hours. The microdialysate was analyzed by ELISA and HPLC/MS. Additionally the cells which attached on the plates were studied ex vivo by histological and biochemical examinations. To investigate systemic effects of bone defects blood plasma samples from rats with and without a bone defect were analyzed.
Results and Conclusions: Protein concentration within the samples varied between 0.06 mg/ml and 0.77 mg/ml. When analyzing proteins, which are involved in fracture healing, by ELISA we were able to detect IL-6, TNF-alpha, TGF-beta1, and VEGF in nearly all microdialysates. A detailed analysis of microdialysates by HPLC/MS showed that the collected proteins could be divided in four groups: proteins from (1) muscle, (2) blood, (3) cell and matrix, and (4) others. Comparison of TGF-beta1 in blood plasma samples from rats with bone defect and sham surgery showed that TGF-beta1 was higher in blood plasma samples from bone defect. It was also possible to detect cells with morpholohical features of fibroblasts attached to the osteosynthesis plates as early as eight hours after surgery.
Microdialysis is a promising novel method to detect proteins in critical size bone defects in vivo that will help to understand and potentially influence bone healing in the early stages.
