Matrix metalloproteinase-9 (gelatinase B) deficiency leads to increased severity of Staphylococcus aureus-triggered septic arthritis

Microbes Infect. 2006 May;8(6):1434-9. doi: 10.1016/j.micinf.2006.01.001. Epub 2006 Mar 29.


Matrix metalloproteinases constitute a family of structurally related endopeptidases that are crucial for the normal turnover of the extracellular matrix. Elevated levels of MMP-9 have been demonstrated in synovial fluids of rheumatoid arthritis patients, and a correlation with the severity of the disease has been described. The aim of this study was to explore the impact of MMP-9 expression on joint inflammation and destruction in a model of bacterially induced septic arthritis. MMP-9 knock-out mice and C57Bl6 congenic controls were inoculated intravenously or intra-articularly with Staphylococcus aureus. Arthritis was evaluated clinically and by means of histology. Zymographic analyses were performed to study ex vivo induction of MMP-9 following exposure to S. aureus. The MMP-9 knock-out mice displayed a significantly higher frequency and severity, but not destructivity, of arthritis than did the wild-type mice. The knock-out mice also proved to harbour an increased number of bacteria locally in joints and systemically in kidneys, possibly by impaired extravasation and recruitment of leukocytes and a deficient early defence against infection. Our findings indicate that deficiency in MMP-9 increases the degree of joint inflammation due to decreased bacterial clearance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arthritis, Infectious / enzymology*
  • Arthritis, Infectious / immunology
  • Arthritis, Infectious / microbiology*
  • Arthritis, Infectious / pathology
  • Cell Growth Processes / physiology
  • Disease Models, Animal
  • Electrophoresis, Polyacrylamide Gel
  • Female
  • Histocytochemistry
  • Interleukin-6 / metabolism
  • Joints / enzymology
  • Joints / immunology
  • Joints / microbiology
  • Joints / pathology
  • Matrix Metalloproteinase 9 / deficiency*
  • Matrix Metalloproteinase 9 / immunology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Staphylococcal Infections / enzymology*
  • Staphylococcal Infections / immunology
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / immunology*


  • Interleukin-6
  • Matrix Metalloproteinase 9