title: Mediation of laser trabeculoplasty-induced matrix metalloproteinase expression by IL-1beta and TNFalpha.
abstract: OBJECTIVE
  Laser trabeculoplasty of the anterior uveal region of the trabecular meshwork induces sustained matrix metafloproteinase expression within the juxtacanalicular region of the meshwork. Studies were conducted to test the hypothesis that a factor mediates this response and to identify the factor.
  
  
  METHODS
  Human anterior segment organ cultures were subjected to laser treatment using standard clinical parameters and were returned to culture for 8 hours. The resultant 8-hour-conditioned culture medium was then tested for factor activity by evaluating its ability to produce two typical trabecular responses to laser treatment, that is, to induce stromelysin expression or to trigger cell division, when applied to fresh organ cultures or to cell cultures. Confocal immunohistochemistry of the laser-treated organ cultures and western immunoblot analysis of the conditioned medium were used to evaluate changes in potential candidates for the factor activity. The ability of the interleukin (IL)-1 receptor antagonist (IL-1ra)- and of tumor necrosis factor alpha (TNFalpha)- blocking antibodies to eliminate the stromelysin induction was evaluated.
  
  
  RESULTS
  Medium conditioned for 8 hours induced typical trabecular cell division in anterior segment organ cultures. Medium conditioned for 8 hours, but not for 30 minutes, induced typical increases in stromelysin expression in these organ cultures and in cell cultures. After 8 hours, both trabecular cells in laser-treated organ cultures and in the conditioned medium contained elevated levels of IL-1beta and TNFalpha. The laser-treated organ cultures contained elevated levels of IL-1alpha, but it was not secreted into the medium. The ability of conditioned media to induce stromelysin expression was partially blocked by either the IL-1ra- or the TNFalpha-blocking antibody.
  
  
  CONCLUSIONS
  Laser trabeculoplasty induces the expression and secretion of both IL-1beta and TNFalpha within the first 8 hours after treatment. These cytokines then mediate increased trabecular stromelysin expression. Putatively, this initiates remodeling of the juxtacanalicular extracellular matrix, a likely site for the aqueous outflow resistance, and thus restores normal outflow facility.
authors.affiliation: Casey Eye Institute, Oregon Health Sciences University, Portland, OR 97201, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Bradley
authors.forename: A M
authors.initials: AM
authors.lastname: Anderssohn
authors.forename: C M
authors.initials: CM
authors.lastname: Colvis
authors.forename: D E
authors.initials: DE
authors.lastname: Parshley
authors.forename: X H
authors.initials: XH
authors.lastname: Zhu
authors.forename: M S
authors.initials: MS
authors.lastname: Ruddat
authors.forename: J R
authors.initials: JR
authors.lastname: Samples
authors.forename: T S
authors.initials: TS
authors.lastname: Acott
mesh_terms: D000818:Animals; D000869:Anterior Eye Segment / Q000378:metabolism / Q000601:surgery*; D019138:Antibodies, Blocking / Q000494:pharmacology; D015153:Blotting, Western; D003470:Culture Media; D017077:Culture Media, Conditioned; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053685:Laser Therapy; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis* / Q000235:genetics; D018613:Microscopy, Confocal; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000378:metabolism; D012795:Sialoglycoproteins / Q000276:immunology; D013552:Swine; D014130:Trabeculectomy / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*
chemical_list: D019138:Antibodies, Blocking; D003470:Culture Media; D017077:Culture Media, Conditioned; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D014409:Tumor Necrosis Factor-alpha; D019278:Matrix Metalloproteinase 3