Research of bacteria related to periapical diseases activate MMP and inactivate TIMP

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Matrix metalloproteinases (MMPs) play a critical role in the homeostasis of the extracellular matrix (ECM). The imbalance between production of MMPs and that of their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), plays an important role in tissue destruction. It has been reported that MMP-1 and MMP-9 are activated by the bacteria associated with the production of periapical diseases. However few reports regarding the activation of pro-MMP-2 and inactivation of TIMP have been published. The purpose of the present study was to evaluate the activation of pro-MMP-2 and inactivation of TIMP in cultured cells.l )Measurement of MMP-2 activityThe supernatant obtained from medium containing PL cells or HT1080 cells and a sonicated bacterial extract (SEE) from P. gingivalis (P.g.) was analyzed by the gelatin zymography method. When PL cells or HT1080 cells were treated with the SBE, visible bands that corresponded to active MMP-2 were observed on the gelatin zymograms.2) Measurement of TIMP-1 and TIMP-2 proteinsThe amount of TIMP-1 was measured by the EIA method of Kodama et al. TIMP-1 was not detected in the supernatant obtained from the medium of cultures of P.g. SBE-treated PL cells. The amount of TIMP-1 and TIMP-2 in the supernatant obtained from HT1080 cell cultures treated with the extract decreased in a P.g. SBE concentration-dependent manner.3) Measurement of TIMP-1 activityAfter a solution of purified TIMP-1 had been reacted with SBE, TIMP-1 retained in the solution was evaluated by gelatin zymography in terms of its inhibitory activity toward MMP-1 or MMP-2. P.g. SEE remarkably decreased the inhibitory activity of TIMP-1 toward MMP-2.