EFFECTS OF INTERLEUKIN-1-BETA ON MATRIX METALLOPROTEINASE-3 LEVELS INHUMAN PERIODONTAL-LIGAMENT CELLS

MATRIX METALLOPROTEINASE-3 (MMP-3), or stromelysin-1, is an enzyme res ponsible for the degradation of a wide range of extracellular matrix p roteins. Increases in MMP-3 activity have been found in several chroni c inflammatory diseases, and this increased activity is thought to be mediated by interleukin-1 beta (IL-1 beta). Because IL-1 beta has been strongly associated with inflammatory periodontal disease, the purpos e of this in vitro study was to investigate the role of IL-1 beta on t he regulation of MMP-3 levels in cells derived from the human periodon tal ligament (PDL). Human PDL cell cultures were treated with IL-1 bet a at varying concentrations (0.01-1.0 ng/ml) for 24 hours prior to ana lysis at either transcript or protein levels. Following the isolation of total RNA, the relative levels of MMP-3 mRNA were determined using reverse transcription-polymerase chain reaction (RT-PCR) with P-32-end -labeled primers. Immunocytochemical detection of MMP-3 protein was pe rformed using polyclonal antibodies to human MMP-3. The results of RT- PCR analysis demonstrated a concentration-dependent increase in MMP-3 mRNA expression, with IL-1 beta treatments of 0.1 and 1.0 ng/ml signif icantly (P < 0.01) increased over those cells not treated with IL-1 be ta. This increase in mRNA expression was paralleled by significant (P < 0.001) changes at the protein level, with an average of 27.6% of the cells stained positive for MMP-3 following IL-1 beta treatment (1.0 n g/ml), compared with control cells showing no positive staining for MM P-3. In conclusion, the results of this study demonstrate that IL-1 be ta upregulates MMP-3 in human PDL cells on both an mRNA and a protein level. These findings suggest possibly important roles for IL-1 beta a nd MMP-3 in both normal turnover and maintenance of the PDL and in the connective tissue degradation associated with periodontal disease.