MATRIX METALLOPROTEINASES-1 AND METALLOPROTEINASES-8 AND TIMP-1 MESSENGER-RNA LEVELS IN NORMAL AND DISEASED HUMAN GINGIVAE

Interstitial collagenases. including matrix metalloproteinase-1 (MMP-1 ) and -8 (MMP-8), serve as initiators of extracellular matrix destruct ion in periodontal disease. Collagenase activities are mainly regulate d by tissue inhibitors of metalloproteinases (TIMPs). We tested the ef fects of inflammation on MMP-1 and MMP-8 gene expression in periodonta l disease. To determine the relative abundance of these mRNAs in gingi va, we used a reverse transcription-polymerase chain reaction (RT-PCR) assay Gingival biopsies were divided into 2 groups; a control group a nd an inflamed group with severe gingivitis or periodontitis. The MMP- 1 mRNA levels were significantly elevated in inflamed gingiva, while t he levels of the MMP-8 transcript were not different in the 2 groups a nd barely detectable by RT-PCR assay. The expression of the TIMP-1 gen e was not altered, and remained higher than any of these other genes i n both control and diseased gingivae. These results suggest that MMP-1 rather than MMP-8 may play an important role in the initiation of col lagen degradation in periodontal disease. However. the possibility rem ains that MMP-8 plays an important role in periodontal tissue destruct ion, since the mRNA abundance and not the enzyme activity was assessed .