The Effect Of Superimposed Vibrations On Chondrocytes Subjected To Dynamic Compressive Loading

Weber J; Waldman S
Orthopeadic Research Society Annual Meeting in Las Vegas, Abstract 1244

Les titres, résumés et légendes des publications sont présentés en anglais.

Introduction: Mechanical stimulation is often used as a means to accelerate and improve the growth and properties of tissue engineered cartilage constructs. However, as cartilage cells (chondrocytes) rapidly desensitize to the imposed stimulus [1], the available window to apply mechanical loading is limited, thereby reducing the effectiveness of this treatment. One approach to mitigate the effects of loading-induced cellular desensitization is through the modification of the applied loading protocols. Specifically, cellular sensitivity to mechanical stimuli can be altered by superimposing mechanical vibrations on the loading waveforms. This approach, termed “stochastic resonance”, has been successfully applied to improve sensitivity in other nonlinear biomedical systems including mechanosensitive cells of the same lineage (e.g. osteocytes [2]). Thus, the purpose of this study was to investigate the effect of stochastic resonance on 3-dimensional chondrocyte cultures subjected to dynamic compressive stimuli.

Discussion: The results of this study demonstrate that the application of superimposed random vibrations during dynamic compressive stimulation can elicit an increased biosynthetic response compared to dynamic compression alone. Effect of superimposed vibrations on matrix synthesis appeared to be additive, suggesting that maximal increases in matrix synthesis could be achieved by optimizing both the compressive and vibrational stimuli. Increases in matrix synthesis appeared to be loosely correlated with increased Ca2+ signaling determined over the entire construct cross-section. When the signaling response was determined in core and periphery of the construct, changes in Ca2+ signaling appeared to exclusively occur in the periphery of the sample. This result is similar to previous studies which have shown that newly synthesized matrix macromolecules are preferentially deposited in the sample periphery as a result of dynamic compressive loading.

Utilisation des équipements

L’étude a examiné une stimulation compressive dynamique avec vibrations aléatoires superposées dans des cultures tridimensionnelles de chondrocytes, en évaluant la synthèse matricielle et la signalisation calcique. Les extraits disponibles n’identifient pas l’appareil de chargement et n’expliquent pas la génération des vibrations. Ils ne permettent donc ni d’établir le rôle du Mach-1 Mechanical Tester ni de confirmer une stimulation en cisaillement.