title: Comparison between chondroprotective effects of glucosamine, curcumin, and diacerein in IL-1beta-stimulated C-28/I2 chondrocytes.
abstract: OBJECTIVE
  To compare the effects of glucosamine (GlcN), curcumin, and diacerein in immortalized human C-28/I2 chondrocytes at the cellular and the gene expression level. This study aimed to provide insights into the proposed beneficial effects of these agents and to assess the applicability of the C-28/I2 cell line as a model for the evaluation of chondroprotective action.
  
  
  METHODS
  Interleukin-1beta (IL-1beta)-stimulated C-28/I2 cells were cultured in the presence of GlcN, curcumin, and diacerein prior to the evaluation of parameters such as viability, morphology and proliferation. The impact of GlcN, curcumin, and diacerein on gene expression was determined using quantitative real-time RT-PCR (qPCR).
  
  
  RESULTS
  At the transcriptional level, 5 mM GlcN and 50 microM diacerein increased the expression of cartilage-specific genes such as aggrecan (AGC) and collagen type II (COL2), while reducing collagen type I (COL1) mRNA levels. Moreover, the IL-1beta-mediated shift in gene expression pattern was antagonized by GlcN and diacerein. These effects were associated with a significant reduction in cellular proliferation and the development of chondrocyte-specific cell morphology. In contrast, curcumin was not effective at lower concentrations but even damaged the cells at higher amounts.
  
  
  CONCLUSIONS
  Both GlcN and diacerein promoted a differentiated chondrocytic phenotype of immortalized human C-28/I2 chondrocytes by altering proliferation, morphology, and COL2/COL1 mRNA ratios. Moreover, both agents antagonized inhibitory effects of IL-1beta by enhancing AGC and COL2 as well as by reducing COL1 mRNA levels.
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria. stefan.toegel@univie.ac.at
authors.forename: S
authors.initials: S
authors.lastname: Toegel
authors.forename: S Q
authors.initials: SQ
authors.lastname: Wu
authors.forename: C
authors.initials: C
authors.lastname: Piana
authors.forename: F M
authors.initials: FM
authors.lastname: Unger
authors.forename: M
authors.initials: M
authors.lastname: Wirth
authors.forename: M B
authors.initials: MB
authors.lastname: Goldring
authors.forename: F
authors.initials: F
authors.lastname: Gabor
authors.forename: H
authors.initials: H
authors.lastname: Viernstein
mesh_terms: D000880:Anthraquinones / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured / Q000378:metabolism; D019902:Chondrocytes / Q000187:drug effects*; D003474:Curcumin / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D005944:Glucosamine / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D053583:Interleukin-1beta / Q000235:genetics; D008954:Models, Biological; D010003:Osteoarthritis / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D020011:Protective Agents / Q000494:pharmacology*
chemical_list: D000880:Anthraquinones; D053583:Interleukin-1beta; D020011:Protective Agents; C025292:diacerein; D003474:Curcumin; D005944:Glucosamine