Ciprofloxacin up-regulates tendon cells to express matrix metalloproteinase-2 with degradation of type I collagen

J Orthop Res. 2011 Jan;29(1):67-73. doi: 10.1002/jor.21196.


Ciprofloxacin-induced tendinopathy and tendon rupture have been previously described, principally affecting the Achilles tendon. This study was designed to investigate the effect of ciprofloxacin on expressions of matrix metalloproteinases (MMP)-2 and -9, tissue inhibitors of metalloproteinase (TIMP)-1 and -2 as well as type I collagen in tendon cells. Tendon cells intrinsic to rat Achilles tendon were treated with ciprofloxacin and then underwent MTT (tetrazolium) assay. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analysis were used, respectively, to evaluate the gene and protein expressions of type I collagen, and MMP-2. Gelatin zymography was used to evaluate the enzymatic activities of MMP-2 and -9. Reverse zymography was used to evaluate TIMP-1 and -2. Immunohistochemical staining for MMP-2 in ciprofloxacin-treated tendon explants was performed. Collagen degradation was evaluated by incubation of conditioned medium with collagen. The results revealed that ciprofloxacin up-regulated the expression of MMP-2 in tendon cells at the mRNA and protein levels. Immunohistochemistry also confirmed the increased expressions of MMP-2 in ciprofloxacin-treated tendon explants. The enzymatic activity of MMP-2 was up-regulated whereas that of MMP-9, TIMP-1 or TIMP-2 was unchanged. The amount of secreted type I collagen in the conditioned medium decreased and type I collagen was degraded after ciprofloxacin treatment. In conclusion, ciprofloxacin up-regulates the expressions of MMP-2 in tendon cells and thus degraded type I collagen. These findings suggest a possible mechanism of ciprofloxacin-associated tendinopathy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Achilles Tendon / drug effects*
  • Achilles Tendon / metabolism
  • Animals
  • Anti-Infective Agents / toxicity*
  • Cell Survival / drug effects
  • Ciprofloxacin / toxicity*
  • Collagen Type I / genetics
  • Collagen Type I / metabolism*
  • Matrix Metalloproteinase 2 / analysis
  • Matrix Metalloproteinase 2 / genetics*
  • Matrix Metalloproteinase 9 / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Tissue Inhibitor of Metalloproteinase-1 / analysis
  • Tissue Inhibitor of Metalloproteinase-2 / analysis
  • Up-Regulation


  • Anti-Infective Agents
  • Collagen Type I
  • Tissue Inhibitor of Metalloproteinase-1
  • Tissue Inhibitor of Metalloproteinase-2
  • Ciprofloxacin
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9