Sonic extracts from a bacterium related to periapical disease activate gelatinase A and inactivate tissue inhibitor of metalloproteinases TIMP-1 and TIMP-2

P>Aim To examine the effects of sonicated bacterial extracts (SBEs) from three related to periapical disease bacteria (Porphyromonas gingivalis, P. endodontalis and F. nucleatum) on the activation of matrix metalloproteinase (MMP-2) and the inactivation of tissue inhibitors of metalloproteinase (TIMP-1 and TIMP-2). Methodology Each SBE was added to cultures of human periodontal ligament (PL) cells or HT1080 cells and their supernatants were analysed by zymography for MMP-2. Each SBE was added to PL cell cultures, and the amount of TIMP-1 was determined by ELISA. P. gingivalis SBE was incubated with HT1080 cell culture supernatants, and the amounts of TIMP-1 and TIMP-2 were determined by ELISA. Statistical analysis was performed with the paired Student's t-test. Results In extracts of PL cells that had been incubated in the presence of P. gingivalis SBE, one representing pro-MMP-2 (72 kDa) and a band corresponding to the active MMP-2 (66 kDa) were observed; but in the other extracts it was not detected. When HT1080 cells were treated with P. gingivalis SBE, the pro-MMPs was processed into 86- and 66-kDa fragments, but in the other extracts, the processing did not occur when the other SBEs were used. When PL cells were incubated with the same SBEs, the amount of TIMP-1 was markedly decreased (P < 0.01), but in the other extracts, it was not. The amounts of both TIMP-1 and TIMP-2 were decreased in a dose-dependent manner when HT1080 cell culture supernatant was incubated with P. gingivalis SBE. Conclusions These findings suggest that P. gingivalis SBE may cause connective tissue to be destroyed, contributing to the process of periapical disease, by activating pro-MMP-2 as well as by inactivating TIMP-1 and TIMP-2.