title: Effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate on adult equine cartilage.
abstract: OBJECTIVE
  To analyze the effect of radiosynovectomy with holmium-166 ferric hydroxide macroaggregate (166Ho-FHMA) on articular cartilage in 6 adult horses.
  
  
  METHODS
  Arthritic changes and mechanical properties of articular cartilage were evaluated with arthroscopy and postmortem microscopic analyses. Glycosaminoglycan content was measured by safranin-O staining combined with digital densitometry, uronic acid analyses, and dimethylene blue binding assay. 35S-sulfate labeling and autoradiography were used to localize proteoglycan synthesis and to characterize proteoglycan structures using SDS-agarose gel electrophoresis. Northern hybridizations were performed to measure the mRNA levels for aggrecan and pro-a1(II) collagen in cartilage samples.
  
  
  RESULTS
  Histological signs of degeneration were present in the articular cartilage of both control and radiosynovectomized equine joints. Radiosynovectomy did not aggravate degenerative changes or significantly alter the matrix glycosaminoglycan content. A slightly decreased size of proteoglycan monomers was observed 2 months after 166Ho-FHMA radiosynovectomy. Tissue analysis of extracted proteoglycans revealed lower 35S incorporation after radiosynovectomy, but corresponding changes could not be observed in aggrecan mRNA levels. Transient downregulation of pro-a1(II) collagen mRNA transcription was observed 5 days after 166Ho-FHMA radiosynovectomy.
  
  
  CONCLUSIONS
  166Ho-FHMA treatment did not markedly affect the composition or morphology of adult articular cartilage showing mild degeneration. However, minor degradation of proteoglycan monomers and transient downregulation of pro-a1(II) collagen mRNA were observed.
authors.affiliation: Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Olli T
authors.initials: OT
authors.lastname: Mäkelä
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Lammi
authors.forename: Hannele
authors.initials: H
authors.lastname: Uusitalo
authors.forename: Minna
authors.initials: M
authors.lastname: Viitanen
authors.forename: Mika M
authors.initials: MM
authors.lastname: Hyttinen
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.forename: Eero
authors.initials: E
authors.lastname: Vuorio
authors.forename: Heikki J
authors.initials: HJ
authors.lastname: Helminen
authors.forename: Riitta-Mari
authors.initials: RM
authors.lastname: Tulamo
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006025:Glycosaminoglycans / Q000378:metabolism; D006736:Horses; D006878:Hydroxides / Q000627:therapeutic use*; D013431:Sulfates / Q000493:pharmacokinetics; D013462:Sulfur Radioisotopes; D013582:Synovial Fluid / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology*; D013585:Synovitis / Q000473:pathology* / Q000628:therapy*
chemical_list: D006025:Glycosaminoglycans; D006878:Hydroxides; D013431:Sulfates; D013462:Sulfur Radioisotopes; C483519:holmium-ferric hydroxide