title: The revitalisation of flexor tendon allografts with bone marrow stromal cells and mechanical stimulation: Anex vivomodel revitalising flexor tendon allografts.
abstract: OBJECTIVE
  The present study describes a novel technique for revitalising allogenic intrasynovial tendons by combining cell-based therapy and mechanical stimulation in anex vivocanine model.
  
  
  METHODS
  Specifically, canine flexor digitorum profundus tendons were used for this study and were divided into the following groups: (1) untreated, unprocessed normal tendon; (2) decellularised tendon; (3) bone marrow stromal cell (BMSC)-seeded tendon; and (4) BMSC-seeded and cyclically stretched tendon. Lateral slits were introduced on the tendon to facilitate cell seeding. Tendons from all four study groups were distracted by a servohydraulic testing machine. Tensile force and displacement data were continuously recorded at a sample rate of 20 Hz until 200 Newton of force was reached. Before testing, the cross-sectional dimensions of each tendon were measured with a digital caliper. Young's modulus was calculated from the slope of the linear region of the stress-strain curve. The BMSCs were labeled for histological and cell viability evaluation on the decellularized tendon scaffold under a confocal microscope. Gene expression levels of selected extracellular matrix tendon growth factor genes were measured. Results were reported as mean ± SD and data was analyzed with one-way ANOVAs followed by Tukey's post hoc multiple-comparison test.
  
  
  RESULTS
  We observed no significant difference in cross-sectional area or in Young's modulus among the four study groups. In addition, histological sections showed that the BMSCs were aligned well and viable on the tendon slices after two-week culture in groups three and four. Expression levels of several extracellular matrix tendon growth factors, including collagen type I, collagen type III, and matrix metalloproteinase were significantly higher in group four than in group three (p < 0.05).
  
  
  CONCLUSIONS
  Lateral slits introduced into de-cellularised tendon is a promising method of delivery of BMSCs without compromising cell viability and tendon mechanical properties. In addition, mechanical stimulation of a cell-seeded tendon can promote cell proliferation and enhance expression of collagen types I and IIIin vitro.Cite this article:J. H. Wu, A. R. Thoreson, A. Gingery, K. N. An, S. L. Moran, P. C. Amadio, C. Zhao. The revitalisation of flexor tendon allografts with bone marrow stromal cells and mechanical stimulation: Anex vivomodel revitalising flexor tendon allografts.Bone Joint Res2017;6:179-185. DOI: 10.1302/2046-3758.63.BJR-2016-0207.R1.
authors.affiliation: Department of Hand Surgery, Beijing Jishuitan Hospital, Beijing, China.
authors.forename: J H
authors.initials: JH
authors.lastname: Wu
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Thoreson
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.
authors.forename: A
authors.initials: A
authors.lastname: Gingery
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: An
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Moran
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Amadio
authors.affiliation: Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA zhao.chunfeng@mayo.edu.
authors.forename: C
authors.initials: C
authors.lastname: Zhao
keywords: BMSCs; Bone marrow stromal cells; Stretch; Tendon allografts revitalisation; Tendon slice; Tissue engineering