Stochastic amplitude-modulated stretching of rabbit flexor digitorum profundus tendons reduces stiffness compared to cyclic loading but does not affect tenocyte metabolismReport as inadecuate




Stochastic amplitude-modulated stretching of rabbit flexor digitorum profundus tendons reduces stiffness compared to cyclic loading but does not affect tenocyte metabolism - Download this document for free, or read online. Document in PDF available to download.

BMC Musculoskeletal Disorders

, 13:222

First Online: 14 November 2012Received: 13 February 2012Accepted: 08 November 2012

Abstract

BackgroundIt has been demonstrated that frequency modulation of loading influences cellular response and metabolism in 3D tissues such as cartilage, bone and intervertebral disc. However, the mechano-sensitivity of cells in linear tissues such as tendons or ligaments might be more sensitive to changes in strain amplitude than frequency. Here, we hypothesized that tenocytes in situ are mechano-responsive to random amplitude modulation of strain.

MethodsWe compared stochastic amplitude-modulated versus sinusoidal cyclic stretching. Rabbit tendon were kept in tissue-culture medium for twelve days and were loaded for 1h-day for six of the total twelve culture days. The tendons were randomly subjected to one of three different loading regimes: i stochastic 2 – 7% random strain amplitudes, ii cyclic RMS 2–4.42% strain and iii cyclic high 2 - 7% strain, all at 1 Hz and for 3,600 cycles, and one unloaded control.

ResultsAt the end of the culture period, the stiffness of the -stochastic- group was significantly lower than that of the cyclic RMS and cyclic high groups both, p < 0.0001. Gene expression of eleven anabolic, catabolic and inflammatory genes revealed no significant differences between the loading groups.

ConclusionsWe conclude that, despite an equivalent metabolic response, stochastically stretched tendons suffer most likely from increased mechanical microdamage, relative to cyclically loaded ones, which is relevant for tendon regeneration therapies in clinical practice.

KeywordsTendon Tensile stiffness Stochastic amplitude-modulation Strain control Proteoglycan production Gene expression Cell activity Electronic supplementary materialThe online version of this article doi:10.1186-1471-2474-13-222 contains supplementary material, which is available to authorized users.

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Author: Thomas H Steiner - Alexander Bürki - Stephen J Ferguson - Benjamin Gantenbein-Ritter

Source: https://link.springer.com/







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