Ibuprofen inhibition of tendon cell migration and down-regulation of paxillin expression.

Sports-related tendon injuries are commonly treated with nonsteroidal antiinflammatory drugs. Tendon healing requires migration of tendon cells to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of ibuprofen on the migration of tendon cells intrinsic to rat Achilles tendon. Whether a correlation exits between this effect and the expression of paxillin, which is a positive regulator of cell spreading and migration, was also investigated. The migration of tendon cells was evaluated ex vivo by counting the number of initial outgrowths from the tendon explants and in vitro by transwell filter migration assay. The spreading of tendon cells in culture was also evaluated microscopically. The mRNA and protein expressions of paxillin were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Dose-dependent ibuprofen inhibition was demonstrated on the migration of tendon cells both ex vivo, and in vitro. Similar inhibition was also observed on the spreading of tendon cells. Suppression of mRNA expression and protein level of paxillin was revealed by RT-PCR and Western blot analyses. The expression of focal adhesion kinase (FAK) and tyrosine phosphorylation of FAK remained unchanged. In conclusion, ibuprofen inhibits tendon cell migration in a process that is probably mediated by the down-regulation of paxillin. Copyright 2006 Orthopaedic Research Society.