title: Loss of transforming growth factor counteraction on interleukin 1 mediated effects in cartilage of old mice.
abstract: OBJECTIVE
  To investigate if a difference exists between young and old mice in the response of articular cartilage to interleukin 1 (IL1) and transforming growth factor beta (TGFbeta) alone or in combination.
  
  
  METHODS
  The interaction of IL1 and TGFbeta was studied in cartilage of young (three months) and old mice (18 months) both in vivo and in vitro. Therefore, IL1, TGFbeta, or IL1 together with TGFbeta was injected into the knee joints of mice on days 1, 3, and 5 before harvest of the patellae on day 6. Alternatively, isolated patellae were stimulated with IL1, TGFbeta, or IL1 together with TGFbeta in culture for 48 hours. Proteoglycan (PG) synthesis and nitric oxide (NO) production were measured.
  
  
  RESULTS
  IL1 inhibited PG synthesis and increased NO production in cartilage of both young and old mice. On the other hand, TGFbeta stimulated PG synthesis and reduced NO production in both age groups. Importantly, TGFbeta was able to counteract IL1 mediated effects on PG synthesis and NO production in young but not in old mice.
  
  
  CONCLUSIONS
  Contrary to the findings in young mice, the cartilage of old animals does not antagonise IL1 effects via TGFbeta. This loss of responsiveness to the pivotal cytokine TGFbeta on effects of IL1 can be important in the initiation and progression of osteoarthritis (OA).
authors.affiliation: Rheumatology Research Laboratory, Department of Rheumatology, University Medical Centre Nijmegen, Nijmegen, 6525 GA, The Netherlands. a.scharstuhl@ncmls.kun.nl
authors.forename: A
authors.initials: A
authors.lastname: Scharstuhl
authors.forename: H M
authors.initials: HM
authors.lastname: van Beuningen
authors.forename: E L
authors.initials: EL
authors.lastname: Vitters
authors.forename: P M
authors.initials: PM
authors.lastname: van der Kraan
authors.forename: W B
authors.initials: WB
authors.lastname: van den Berg
mesh_terms: D000367:Age Factors; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects* / Q000378:metabolism; D004359:Drug Therapy, Combination; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis; D010329:Patella / Q000187:drug effects / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D007375:Interleukin-1; D011509:Proteoglycans; D016212:Transforming Growth Factor beta; D009569:Nitric Oxide