Abstract
The purpose of this experiment was to investigate the role of human periodontal ligament (PL) cells, which are non-inflammatory and typical resident cells in periapical connective tissue, in periapical tissue disease. We examined the effects of sonica-tcd bacterial extracts (SBE) from 4 bacterial species, Porphyromonas endodontalis (PE), For-phyromonas gingivalis (PG), Prevotella intermedia (PI) and Fusobacterium nucleatum (FN), which are closely associated with periapical disease, on extracellular matrix (ECM) degradation by PL cells. PL cells were obtained from periodontal ligament tissue of freshly extracted human teeth and used for experiments at passage levels 5-9. After the cells had reached confluence, they were further incubated for 48 hours in culture medium with SBE (final concentration: 10μg protein/ml). We determined the activities of matrix metallo-proteinases (interstitial collagenase, MMP-1: gelatinase A, MMP-2) and the concentrations of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in the medium.
The results were as follows:
1. Production of active MMP-1 was not in-creased by any of the SBE tested, however total MMP-1 production was slightly inhibited by PG and PI, whereas it was accelerated by FN.
2. Production of active MMP-2 was significantly accelerated by PE and PG, whereas total MMP-2 production was slightly inhibited by PI.
3. TIMP-1 production was increased by PG and FN.
4. TIMP-2 production was markedly elevated by all SBE. In summary, each SBE derived from these bacte-rial species appeared to show differing effects on the induction of MMPs and TIMPs produced by PL cells. Our findings suggest that PL cells stimulated by extracts from PE, PG, PI, and FN may be involved in the pathogenesis of periapical disease.
