title: Tissue renin-angiotensin system in the intervertebral disc.
abstract: METHODS
  Immunohistochemical and biochemical analyses of the rat intervertebral disc (IVD) tissue renin-angiotensin system (tRAS).
  
  
  OBJECTIVE
  To examine the expression and function of tRAS in the rat IVD.
  
  
  BACKGROUND
  Angiotensin II (Ang II), the major effector of tRAS, is a hormone that contributes to inflammation and fibrosis in many organs. The expression of tRAS in the rat IVD has not been determined.
  
  
  METHODS
  tRAS expression in rat and bovine IVDs was examined using real-time polymerase chain reaction (rat) and immunohistochemistry (rat and bovine). Rat annulus fibrosus cells in monolayer culture were used to examine the biological role of tRAS in vitro. The effect of Ang II peptide on extracellular matrix metabolism was assessed by real-time polymerase chain reaction.
  
  
  RESULTS
  mRNA of tRAS components, including angiotensin converting enzyme, Ang II, Ang II receptor type 1, Ang II receptor type 2, and Cathepsin D (a renin-like enzyme), was clearly confirmed by real-time polymerase chain reaction analysis. In rat and bovine annulus fibrosus and nucleus pulposus cells in monolayer culture, immunohistochemical analysis showed that each tRAS component was clearly expressed. In rat IVD tissues, immunoreactivity to each antibody for tRAS components was also observed. Proliferation of rat annulus fibrosus cells was mildly stimulated by Ang II peptide. Ang II peptide also had minor stimulatory effect on the expression of the extracellular matrix components, growth factors, and catabolic proteins.
  
  
  CONCLUSIONS
  Our results demonstrate for the first time that the tRAS components necessary to activate tRAS have been found in the normal rat IVD at both mRNA and protein levels. To elucidate the association between tRAS and the process of IVD degeneration, the expression and function of tRAS in the human degenerated IVD should be examined in a future study.
authors.affiliation: Departments of Orthopaedic Surgery, Mie University Graduate School of Medicine, Mie, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Morimoto
authors.forename: Koji
authors.initials: K
authors.lastname: Akeda
authors.forename: Ryu
authors.initials: R
authors.lastname: Iida
authors.forename: Akinobu
authors.initials: A
authors.lastname: Nishimura
authors.forename: Masaya
authors.initials: M
authors.lastname: Tsujii
authors.forename: Shuji
authors.initials: S
authors.lastname: Obata
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kasai
authors.forename: Atsumasa
authors.initials: A
authors.lastname: Uchida
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sudo
mesh_terms: D000804:Angiotensin II / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002402:Cathepsin D / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism*; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D000804:Angiotensin II; D007703:Peptidyl-Dipeptidase A; D002402:Cathepsin D