Bone formation in rabbit cancellous bone explant culture model is enhanced by mechanical load
Open Access
- 19 April 2013
- journal article
- research article
- Published by Springer Science and Business Media LLC in BioMedical Engineering OnLine
- Vol. 12 (1), 35-15
- https://doi.org/10.1186/1475-925x-12-35
Abstract
Background When studying and designing an artificial bone in vitro with similar features and functionality of natural bone by tissue engineering technology, the culturing environment, especially the mechanical environment is supposed to be an important factor, because a suitable mechanical environment in vitro may improve the adaptability of the planted-in tissue engineering bone in the body. Unfortunately, up to now, the relationship between mechanical stimuli and natural bone growth has not yet been precisely determined, and it is so imperative for a prior study on effect of mechanical loading on growth of the natural bone cultured in vitro. Methods Under sterile conditions, explant models of rabbit cancellous bone with 3 mm in thickness and 8 mm in diameter were prepared and cultured in a dynamic loading and circulating perfusion bioreactor system. By Micro-CT scanning, a 3D model for finite element (FEM) analysis was achieved. According to the results of FEM analysis and physiological load bearing capacity of the natural bone, these models were firstly subjected to mechanical load with 1Hz frequency causing average apparent strain of 1000 μϵ, 2000 μϵ, 3000 μϵ and 4000 μϵ respectively for 30 min every day, activities of alkaline phosphatase (AKP) were detected on the 5th and the 14th loading day and on the 14th and the 21st day, mechanical properties, tissue mineral density (TMD) of the bone explant models were investigated and Von-kossa staining and fluorescence double labeling assays were conducted to evaluate whether there were fresh osteoid in the bone explant models. In addition, Western blot, Elisa and Real-time PCR were employed to analyze expression of Collagen-I (COL-1), bone morphogenetic protein-2 (BMP-2) and osteoprotegerin (OPG) protein and RNA. Results The explant models of rabbit cancellous bone prepared under sterile conditions grew well in the bioreactor system. With the increasing culturing time and load levels, bone explant models in groups with 1000 μϵ and 2000 μϵ average apparent strain experienced improving mechanical properties and TMD (P<0.05), and results of Von-kossa staining and fluorescence double labeling also showed apparent fresh osteoid formation. Under the same loading conditions, a up-regulations in protein and RNA of COL-1, BMP-2 and OPG were detected, especially, relative genes notably expressed after 21 days. Conclusion Our study demonstrated that mechanical load could improve function and activity of osteoblasts in explant models of cancellous bone. Through regulations of COL-1, OPG and BMP-2 secreted by osteoblasts, the mechanical load could improve the tissue structural density and stiffness due to formation of fresh osteoid.Keywords
This publication has 33 references indexed in Scilit:
- Mechanical Strain Regulates Osteoblast Proliferation through Integrin-Mediated ERK ActivationPLOS ONE, 2012
- Functionalisation of PLLA nanofiber scaffolds using a possible cooperative effect between collagen type I and BMP-2: impact on growth and osteogenic differentiation of human mesenchymal stem cellsJournal of Materials Science: Materials in Medicine, 2011
- An adaptation model for trabecular bone at different mechanical levelsBioMedical Engineering OnLine, 2010
- Tumor Necrosis Factor α Represses Bone Morphogenetic Protein (BMP) Signaling by Interfering with the DNA Binding of Smads through the Activation of NF-κBOnline Journal of Public Health Informatics, 2009
- Cyclic strain induces FosB and initiates osteogenic differentiation of mesenchymal cellsExperimental and Toxicologic Pathology, 2008
- WITHDRAWN: Novel cyclin-dependent kinase (CDK1/2) inhibitor induced retinopathy in CD1 and B6C3F1 miceExperimental and Toxicologic Pathology, 2008
- In Vivo Mechanical Loading Modulates Insulin-Like Growth Factor Binding Protein-2 Gene Expression in Rat OsteocytesCalcified Tissue International, 2007
- Effects of Transforming Growth Factor β1 on Bonelike Tissue Formation in Three-Dimensional Cell Culture. I. Culture Conditions and Tissue FormationTissue Engineering, 2004
- Control of osteoblast function and regulation of bone massNature, 2003
- Osteoclastogenesis Inhibitory Factor (OCIF) Directly Inhibits Bone-Resorbing Activity of Isolated Mature OsteoclastsBiochemical and Biophysical Research Communications, 1998