The role of insulin-like growth factor-I in hyaluronan mediated repair of cultured cartilage explants.
OBJECTIVE
To test whether hyaluronan (HA) restores proteoglycan (PG) in fibronectin fragment (Fn-f) damaged cartilage through activities of insulin-like growth factor 1 (IGF-1).


METHODS
Bovine cartilage explants were studied.


METHODS
Cartilage PG content was measured by a dye binding assay. PG synthesis was measured by incorporation of radiolabeled sulfate. Release of IGF-1 from explants was measured by ELISA.


RESULTS
Higher mass HA forms were more reparative than smaller and enhanced PG synthesis in explants, but not in monolayer cultures. Higher mass HA enhanced PG synthesis and retention of IGF-1 within the explants while IGF-1 binding proteins decreased activities of HA.


CONCLUSIONS
The reparative effects of HA appear to involve enhanced PG synthesis through IGF-1 and requires cartilage matrix.
Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Box 9037, Grand Forks, ND 58202, USA. ghomandb@medicine.nodak.edu
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Homandberg
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Ummadi
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Kang
D000818:Animals; D002356:Cartilage / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D002417:Cattle; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D006820:Hyaluronic Acid / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology; D008970:Molecular Weight; D011509:Proteoglycans / Q000096:biosynthesis; D046509:Tissue Culture Techniques; D014945:Wound Healing / Q000187:drug effects*
D005353:Fibronectins; D011509:Proteoglycans; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D006820:Hyaluronic Acid