REDUCTION OF MATRIX METALLOPROTEINASE 8-NEUTROPHIL COLLAGENASE LEVELSDURING LONG-TERM DOXYCYCLINE TREATMENT OF REACTIVE ARTHRITIS

The aim of this work was to determine whether human polymorphonuclear neutrophilic interstitial collagenase (matrix metalloproteinase 8 [MMP -8]) levels are reduced during long-term doxycycline treatment in huma ns with reactive arthritis. Serum MMP-8 levels were reduced (mean +/- standard error of the mean, 678.9 +/- 185.6 versus 491.2 +/- 144.8 ng of MMP-8 per ml), but not statistically significantly. However, the re duction of salivary MMP-8 levels was statistically significant (3,729 +/- 1,905.3 versus 1,866 +/- 780.0 ng of MMP-8 per ml, P < 0.05). This study demonstrated that a 2-month regimen of doxycycline can reduce M MP-8 levels in serum and especially in body fluids (i.e., saliva) cont aining inflammatory exudates and thus may contribute to reduced tissue destruction.