It has been suggested that increased number and activity of phagocytes in pericxlontitis lesion results in a high degree of reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, nitric oxide and peroxynitrite. There are few reports on the relationship between ROS and MMPs expressions in gingival fibrob last. We studied to elucidate whether and how ROS, especially nitric oxide affects the MMP expression.
Human gingival fibroblasts and HT1080 cells (human fibrosarcoma sell line as reference) were grown in DMEM supplemented with 10 mM HEPES, 50 mg/L gentamicin, and 10% heat inactivated fetal bovine serum with addition (>f various reactive oxygen species (ROS). Culture media conditioned by cells were examined by gelatin zymognaphy. HT1080 cells expressed proMMP-2 and proMMP-9, but human gingival fibroblasts (HG F) produced only proMMP-2. Hydrogen peroxide upregulated MMP-9 expression in HT1080 cells, whereas in human gingival fibroblast SNP treatment showed marked increase in MMP-2 level compared to other ROS. These results Suggest that the effects of ROS on MMPs expressions are cell-type specific. RT-PCR for MMP-2 and TIMP-2 m-RNA were performed using total RNA from cultured cells under the influence various kinase inhibitors. In HT1080 cells, treatment with FPTI III (Ras processing inhibitor) and LY294002 (P13-kinase inhibitor) resulted in inhibition of MMP-2 and MMP-9 expressions, suggesting that Ras/P13-kinase pathway is important fn- MMPs expression in HT1080 cells. In gingival fibroblasts, treatment with FPTI III and PDTC (NFkB inhibitor) showed marked decrease in MMP-2 regardless of the of SNP, suggesting that Ras/NF-kB could be the key pathway for NO-induced MMP-2 expression in gingival fibroblasts.
This study showed that ROS, especially nitric oxide, could be the critical mediator of periodontal disease progression through control of MMP-2 expression in gingival fibroblasts possibly via Ras/NF-kB pathway.
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