title: Sensitivity of anulus fibrosus cells to interleukin 1 beta. Comparison with articular chondrocytes.
abstract: METHODS
  Anulus fibrosus cells from rabbits were grown in primary culture 1) to study their ability to produce prostaglandin E2 and Type II phospholipase A2, and to express stromelysin-1 messenger ribonucleic acid; and 2) to study the effect of interleukin 1 beta on this production and on proteoglycan aggregation.
  
  
  OBJECTIVE
  To investigate the potency of anulus fibrosus cells to respond to interleukin 1 beta by producing degradative and inflammatory agents as compared with the potency of articular chondrocytes in the same animal.
  
  
  BACKGROUND
  Interleukin 1 beta has been implicated in the degradation of intervertebral discs. The way anulus fibrosus cells differ from articular chondrocytes in their responses to interleukin 1 beta remains to be established.
  
  
  METHODS
  Anulus fibrosus cells and articular chondrocytes were obtained from young rabbits, grown in primary culture, and incubated with interleukin 1 beta. The newly synthesized proteoglycan was measured by labeling with [35S]-sulfate. Proteoglycan aggregation was analyzed by the elution profile on Sepharose 2B columns. The contents of collagen Type II and stromelysin-1 messenger ribonucleic acid were assessed by Northern blot analysis. The Type II phospholipase A2 activity was measured using a fluorometric substrate. Prostaglandin E2 production was evaluated by radioimmunoassay.
  
  
  RESULTS
  Anulus fibrosus cells had 2.5-fold less Type II collagen messenger ribonucleic acid than articular chondrocytes, and interleukin 1 beta had no significant effect on this. Anulus fibrosus cells synthesized and secreted four-fold less proteoglycan than articular chondrocytes. Interleukin 1 beta reduced the anulus fibrosus content of total [35S]-sulfated proteoglycan by 35% (P < 0.01), and that of articular cells by 41% and decreased proteoglycan aggregation. Interleukin 1 beta induced the production of stromelysin-1 messenger ribonucleic acid in both cell types. The stromelysin-1 messenger ribonucleic acid content of anulus fibrosus cells was one half that of articular cells. Interleukin 1 beta increased the production of prostaglandin E2 and caused a dose-dependent secretion of Type II phospholipase A2 activity in both cell types. Its effect was 2.5-fold lower in anulus fibrosus cells than in articular chondrocytes.
  
  
  CONCLUSIONS
  Anulus fibrosus cells can be stimulated by interleukin 1 beta to produce factors implicated in local degradative and inflammatory processes. This production is associated with decreased proteoglycan aggregation. Anulus fibrosus cells respond slightly less well to interleukin 1 beta in vitro than do articular cells.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM) U30, Hôpital Necker-Enfants malades, Université René Descartes, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Rannou
authors.forename: M T
authors.initials: MT
authors.lastname: Corvol
authors.forename: C
authors.initials: C
authors.lastname: Hudry
authors.forename: P
authors.initials: P
authors.lastname: Anract
authors.forename: M F
authors.initials: MF
authors.lastname: Dumontier
authors.forename: L
authors.initials: L
authors.lastname: Tsagris
authors.forename: M
authors.initials: M
authors.lastname: Revel
authors.forename: S
authors.initials: S
authors.lastname: Poiraudeau
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D004247:DNA / Q000032:analysis; D015232:Dinoprostone / Q000096:biosynthesis; D007375:Interleukin-1 / Q000494:pharmacology*; D007403:Intervertebral Disc / Q000166:cytology* / Q000378:metabolism*; D010741:Phospholipases A / Q000096:biosynthesis; D054467:Phospholipases A2; D011509:Proteoglycans / Q000096:biosynthesis; D012313:RNA / Q000032:analysis; D011817:Rabbits
chemical_list: D007375:Interleukin-1; D011509:Proteoglycans; D012313:RNA; D004247:DNA; D010741:Phospholipases A; D054467:Phospholipases A2; D015232:Dinoprostone