Physiological strains remodel extracellular matrix and cell–cell adhesion in osteoblastic cells cultured on alumina-coated titanium alloy

Abstract : The effects of mechanical strains on cellular activities were assessed in an in vitro model using human osteoblastic MG-63 cells grown on titanium alloy discs coated with porous alumina and exposed to chronic intermittent loading. Strain was applied with a Dynacell® device for three 15-min sequences per day for several days with a magnitude of 600 με strain and a frequency of 0.25 Hz. We have previously demonstrated that this regimen increased alkaline phosphatase activity in confluent cultures on ceramic coated titanium (alumina and hydroxyapatite) (Biomaterials 24 (2003) 3139). In this study, we analysed the production of bone matrix proteins. Osteocalcin secretion quantified by ELISA between day 5 and 11 was not affected by mechanical strain. Strain had even no quantifiable effect on collagen production from day 1 to 5 as measured by carboxy terminal collagen type I propeptide release. On the other hand, stress stimulation resulted in increased expression of fibronectin (FN) measured by Western blot after 1 day stretching. This upregulation of FN production was followed by reorganisation of the FN network after 5 days stretching observed by immunostaining. The receptors for collagen and FN, α2β15β1 and β1 integrins were not quantitatively affected by the strains as measured by flow cytometry. A modification of cell morphology was seen after 5 days of loading that appeared to increase cell spreading, implying consequences on intercellular contacts. For this reason, N, C11 and E-adherins were examined. We noted a selective effect characterised by increased expression of N-cadherin using both RT-PCR and Western blot analyses. We concluded that reinforcement of cell–cell adhesion and remodelling of the FN network are important adaptive responses to physiological strains for human osteoblasts grown on alumina-coated biomaterials.
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Biomaterials, Elsevier, 2004, 25 (13), pp.2565-2575. 〈10.1016/j.biomaterials.2003.09.026〉
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https://hal-emse.ccsd.cnrs.fr/emse-00506049
Contributeur : Pierre Charles Pinoli <>
Soumis le : mardi 27 juillet 2010 - 09:03:21
Dernière modification le : jeudi 11 janvier 2018 - 06:20:17

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Fabrice Di Palma, Annette Chamson, Marie-Hélène Lafage-Proust, Paul Jouffrey, Odile Sabido, et al.. Physiological strains remodel extracellular matrix and cell–cell adhesion in osteoblastic cells cultured on alumina-coated titanium alloy. Biomaterials, Elsevier, 2004, 25 (13), pp.2565-2575. 〈10.1016/j.biomaterials.2003.09.026〉. 〈emse-00506049〉

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