title: Positive feedback loop of interleukin-1beta upregulating production of inflammatory mediators in human intervertebral disc cells in vitro.
abstract: OBJECTIVE
  Interleukin-1beta (IL-1beta) induces neurological symptoms in intervertebral disc herniation (IDH). Recently, the existence of a positive feedback loop of IL-1beta, which encourages an inflammatory reaction or degeneration in the cells of tendon, has been reported. The authors hypothesized that there is a positive feedback loop of IL-1beta in the cells of IDH.
  
  
  METHODS
  Eight human intervertebral disc specimens were harvested during spinal surgery for lumbar disc herniation. The cells were stimulated in serum-free medium with or without exogenous IL-1beta. The messenger RNA (mRNA) was extracted for reverse-transcription polymerase chain reaction (PCR) and real-time PCR to quantify the mRNA of endogenous IL-1beta, IL-6, cyclooxygenase-2 (COX-2), and matrix metalloproteinases (MMPs). The cells were then stimulated in serum-free medium with or without exogenous IL-1beta, and then exogenous IL-1beta was removed. After 2, 4, and 6 days, the medium was collected, and enzyme-linked immunosorbent assay was used to measure the protein concentration of endogenous IL-1beta. The mRNA expressions of endogenous IL-1beta, IL-6, COX-2, and MMPs were increased significantly depending on the concentration of exogenous IL-1beta. The protein concentration of endogenous IL-1beta was increased over time.
  
  
  CONCLUSIONS
  There was a positive feedback loop of IL-1beta in the cells of IDH. Furthermore, the productions of IL-6, COX-2, MMP-1, and MMP-3 were upregulated as a result of the increasing concentration of IL-1beta in a positive feedback loop of IL-1beta. The authors concluded that this positive feedback loop of IL-1beta upregulated the production of mediators and thus can cause cessation of symptoms in IDH.
authors.affiliation: Department of Orthopaedic Surgery, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Jimbo
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Park
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Yokosuka
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Sato
authors.forename: Kensei
authors.initials: K
authors.lastname: Nagata
mesh_terms: D000293:Adolescent; D000328:Adult; D018929:Cell Culture Techniques; D005260:Female; D006801:Humans; D007249:Inflammation; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis; D007403:Intervertebral Disc / Q000166:cytology* / Q000276:immunology*; D007405:Intervertebral Disc Displacement / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D019278:Matrix Metalloproteinase 3; D020781:Matrix Metalloproteinase 1