title: Programmable mechanical stimulation influences tendon homeostasis in a bioreactor system.
abstract: Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical/pathological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0-9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP-1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management.
authors.affiliation: Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, M Block, QE2 Medical Centre, Nedlands, Crawley, Western Australia 6009, Australia.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Lin
authors.forename: Robert E
authors.initials: RE
authors.lastname: Day
authors.forename: Bruce
authors.initials: B
authors.lastname: Gardiner
authors.forename: Euphemie
authors.initials: E
authors.lastname: Landao-Bassonga
authors.forename: Jonas
authors.initials: J
authors.lastname: Rubenson
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Kirk
authors.forename: David W
authors.initials: DW
authors.lastname: Smith
authors.forename: David G
authors.initials: DG
authors.lastname: Lloyd
authors.forename: Gerard
authors.initials: G
authors.lastname: Hardisty
authors.forename: Allan
authors.initials: A
authors.lastname: Wang
authors.forename: Qiujian
authors.initials: Q
authors.lastname: Zheng
authors.forename: Ming H
authors.initials: MH
authors.lastname: Zheng
mesh_terms: D000125:Achilles Tendon / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001696:Biomechanical Phenomena / Q000502:physiology; D019149:Bioreactors; D002452:Cell Count; D048430:Cell Shape; D024061:Collagen Type III / Q000737:chemistry; D005109:Extracellular Matrix; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D011817:Rabbits; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology*; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods*
chemical_list: D024061:Collagen Type III