Prevotella Intermedia Regulates MMPs Production in Human Periodontal Ligament Cells

Objectives: Matrix Metalloproteinases (MMPs) are a group of zinc and calcium dependent proteinases capable of degrading extracellular matrix (ECM) and basement membrane components. They play pivotal roles in pathological conditions such as cancer, rheumatoid arthritis and chronic periodontitis. Prevotella intermedia is a black-pigmented, anaerobic rod and it has been reported to be a major periodontal pathogen. Although there were some studies concerning the virulence factors of this bacterium, to date, little is known about its effects on MMPs production. Therefore, the aim of this study was to examine its effects on MMPs production in primary human periodontal ligament (hPDL) cells.

Method: hPDL cells were cultured in DMEM supplemented with 10% fetal calf serum and antibiotics. 1Χ10⁵cells /ml were seeded in 24 well plates. After reaching confluence, the cells were rinsed with serum-free medium and silenced overnight. The cells were then stimulated with various concentrations of P. intermedia ATCC 25611 supernatants. At 3, 6, 14 and 24 hours, conditioned culture media were withdrawn and total RNA was extracted. MMPs mRNA expression was determined by RT-PCR. MMP-2 and MMP-9 protein production was measured by gelatin zymography and MMP-1, -3, TIMP-1, TIMP-2 production was examined by ELISA.

Results: P. intermedia dose and time dependently induced MMP-9 expression and up-regulate TIMP-1 expression at both mRNA and protein levels. It significantly down-regulate MMP-3 and TIMP-2 expression. However, it exerted no or little influence on MMP-1 and MMP-2 expression in hPDL cells.

Conclusions: This study demonstrated that P. intermedia regulate MMPs production in hPDL cells. The disturbance of MMPs production in hPDL cells caused by P. intermedia may contribute to periodontal tissue destruction during chronic periodontitis.