title: Pulsed electromagnetic fields preserve proteoglycan composition of extracellular matrix in embryonic chick sternal cartilage.
abstract: The influence of pulsed electromagnetic fields (PEMF) on proteoglycan composition in cartilage extracellular matrix has been investigated. Day 16 embryonic chick sternal cartilage was explanted to culture and exposed for 3 h per day for 2 days to a repetitive single-pulse PEMF with frequency of 15 Hz and peak magnetic field of 1.25 G. PEMF treatment did not affect cell proliferation, as indicated by [3H]thymidine incorporation, but significantly stimulated the retention of glycosaminoglycans in the explants and reduced the release of glycosaminoglycans into the media. Determination of incorporation of [35S]sulfate and [3H]N-acetylglucosamine into proteoglycans in vitro and breakdown of in ovo labelled [35S]sulfated proteoglycans in vitro showed that PEMF treatment significantly suppressed the synthesis of proteoglycans and the degradation of both newly synthesized and pre-existing proteoglycans. Sepharose CL-2B chromatography demonstrated that PEMF did not affect either the size distribution of newly synthesized and pre-existing [35S]sulfated proteoglycans or their ability to aggregate with hyaluronate. Sepharose CL-6B chromatography followed by cellulose acetate electrophoresis revealed that the chain length and degree of sulfation of [35S]sulfated glycosaminoglycans were identical in control and PEMF-treated cultures. It is concluded that PEMF treatment preserved extracellular matrix integrity of cultured cartilage explants by down-regulating proteoglycan synthesis and degradation in a co-ordinated manner without affecting their gross structural nature.
authors.affiliation: Department of Veterinary Basic Sciences, The Royal Veterinary College, London, UK. hliu@rvc.ac.uk
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: P
authors.initials: P
authors.lastname: Lees
authors.forename: J
authors.initials: J
authors.lastname: Abbott
authors.forename: J A
authors.initials: JA
authors.lastname: Bee
mesh_terms: D000818:Animals; D002356:Cartilage / Q000737:chemistry* / Q000196:embryology; D002642:Chick Embryo; D003094:Collagen / Q000032:analysis; D004247:DNA / Q000096:biosynthesis; D004574:Electromagnetic Fields; D005109:Extracellular Matrix / Q000737:chemistry / Q000528:radiation effects*; D006025:Glycosaminoglycans / Q000032:analysis; D009924:Organ Culture Techniques; D011509:Proteoglycans / Q000032:analysis* / Q000378:metabolism; D013249:Sternum
chemical_list: D006025:Glycosaminoglycans; D011509:Proteoglycans; D003094:Collagen; D004247:DNA