title: Tumour necrosis factor-alpha selectivity modulates expression of collagen genes in rat granulation tissue.
abstract: OBJECTIVE
  To study the effects of tumour necrosis factor-alpha (TNF-alpha) on granulation tissue in rats.
  
  
  METHODS
  Animal experiment.
  
  
  METHODS
  University Hospital, Finland.
  
  
  METHODS
  48 rats in 6 groups.
  
  
  METHODS
  The test implants were treated with either a single or daily injections of 200 ng of TNF-alpha. The samples were collected 4 and/or 7 days postoperatively.
  
  
  METHODS
  Pro alpha 1 (I) and pro alpha 1 (III) collagen mRNA concentrations, hydroxyproline, nitrogen, uronic acids, and hexosamine content of the sponge; and ingrowth of new granulation tissue into the sponge.
  
  
  RESULTS
  A single application of TNF-alpha resulted in no significant differences between the groups. After daily applications of TNF-alpha the accumulation of collagen hydroxyproline and volume of ingrowth of granulation tissue were significantly lower than in the controls. After 7 days there were significant reductions in the concentrations of RNA-ribose, nitrogen, and uronic acids. Daily injections of TNF-alpha reduced pro alpha 1 (I) collagen mRNA concentrations but those of pro alpha 1 (III) collagen mRNA levels were not lowered to the same extent.
  
  
  CONCLUSIONS
  Repeated application of TNF-alpha was required to reduce the synthesis of collagen. This down-regulation was selective as pro alpha 1 (I) collagen mRNA concentrations were lowered more than those of pro alpha 1 (III) collagen mRNA.
authors.affiliation: Department of Surgery, University of Turku, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Rapala
authors.forename: J
authors.initials: J
authors.lastname: Peltonen
authors.forename: J
authors.initials: J
authors.lastname: Heino
authors.forename: H
authors.initials: H
authors.lastname: Kujari
authors.forename: J P
authors.initials: JP
authors.lastname: Pujol
authors.forename: J
authors.initials: J
authors.lastname: Niinikoski
authors.forename: M
authors.initials: M
authors.lastname: Laato
mesh_terms: D000818:Animals; D003094:Collagen / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D006099:Granuloma; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D003094:Collagen