title: Effect of pulsed electromagnetic fields on proteoglycan biosynthesis of articular cartilage is age dependent.
abstract: OBJECTIVE
  To investigate the effects of a pulsed electromagnetic field (EMF) on articular cartilage matrix biosynthesis with regard to age and cartilage damage using a matrix depleted cartilage explant model.
  
  
  METHODS
  Cartilage explants were obtained from metacarpophalangeal joints of calves and adult cows. After depletion of the extracellular matrix by trypsin digestion, samples were maintained in serum-free basal medium with and without the addition of interleukin 1beta (IL1beta). Half the samples were subjected to an EMF for 24 minutes daily; the other half were left untreated. Undigested and untreated explants served as negative controls. After 7 days, biosynthesis of matrix macromolecules was assessed by [35S]sulphate incorporation and values were normalised to hydroxyproline content.
  
  
  RESULTS
  The EMF increased matrix macromolecule synthesis in undigested, untreated explants (p<0.009). In matrix depleted samples the EMF had no stimulatory effect on proteoglycan biosynthesis. IL1beta significantly decreased the de novo synthesis of matrix macromolecules (p<0.00004) in young and adult samples, but an EMF partly counteracted this inhibitory effect in cartilage samples from young, but not old animals.
  
  
  CONCLUSIONS
  EMF promoted matrix macromolecule biosynthesis in intact tissue explants but had no stimulatory effect on damaged articular cartilage. The supressive effects of IL1beta were partially counteracted by EMF exposure, exclusively in cartilage derived from young animals. An EMF has age dependent chondroprotective but not structure modifying properties when cartilage integrity is compromised.
authors.affiliation: Department of Internal Medicine III, Allgemeines Krankenhaus, Waehringer Guertel 18-20, A-1090, Medical University of Vienna, Austria. klaus.bobacz@meduniwien.ac.at
authors.forename: K
authors.initials: K
authors.lastname: Bobacz
authors.forename: W B
authors.initials: WB
authors.lastname: Graninger
authors.forename: L
authors.initials: L
authors.lastname: Amoyo
authors.forename: J S
authors.initials: JS
authors.lastname: Smolen
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D004574:Electromagnetic Fields; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005260:Female; D007375:Interleukin-1 / Q000494:pharmacology; D008662:Metacarpophalangeal Joint; D046509:Tissue Culture Techniques
chemical_list: D016326:Extracellular Matrix Proteins; D007375:Interleukin-1