title: Upregulation of matrix synthesis in chondrocyte-seeded agarose following sustained bi-axial cyclic loading.
abstract: OBJECTIVE
  The promotion of extracellular matrix synthesis by chondrocytes is a requisite part of an effective cartilage tissue engineering strategy. The aim of this in vitro study was to determine the effect of bi-axial cyclic mechanical loading on cell proliferation and the synthesis of glycosaminoglycans by chondrocytes in three-dimensional cultures.
  
  
  METHODS
  A strain comprising 10% direct compression and 1% compressive shear was applied to bovine chondrocytes seeded in an agarose gel during two 12-hour conditioning periods separated by a 12-hour resting period.
  
  
  RESULTS
  The bi-axial-loaded chondrocytes demonstrated a significant increase in glycosaminoglycan synthesis compared with samples exposed to uni-axial or no loading over the same period (p<0.05). The use of a free-swelling recovery period prior to the loading regime resulted in additional glycosaminoglycan production and a significant increase in DNA content (p<0.05), indicating cell proliferation.
  
  
  CONCLUSIONS
  These results demonstrate that the use of a bi-axial loading regime results in increased matrix production compared with uni-axial loading.
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia. bpingguan@um.edu.my
authors.forename: Belinda
authors.initials: B
authors.lastname: Pingguan-Murphy
authors.forename: Illida
authors.initials: I
authors.lastname: Nawi
mesh_terms: D000818:Animals; D002417:Cattle; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D019245:Compressive Strength; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000096:biosynthesis*; D012685:Sepharose; D013314:Stress, Mechanical; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods; D015854:Up-Regulation / Q000502:physiology*
chemical_list: D006025:Glycosaminoglycans; D012685:Sepharose