Expression of matrix metalloproteinase-1, matrix metalloproteinase-2 and extracellular metalloproteinase inducer in human periodontal ligament cells stimulated with interleukin-1beta

Background and Objectives: Matrix metalloproteinases (MMPs), produced by both infiltrating and resident cells of the periodontium, play important roles in physiologic and pathologic events. Both interleukin-1beta and extracellular MMP inducer can stimulate the expression of MMPs, which in turn leads to breakdown of the periodontium. However, it is currently unknown whether interleukin-1beta up-regulates MMPs through stimulating the expression of extracellular MMP inducer. The aims of this study were to investigate the effect of interleukin-1beta on the expression of MMP-1, MMP-2 and extracellular MMP inducer in human periodontal ligament cells and to evaluate whether the regulation of MMP-1 and MMP-2 by this cytokine occurred through an effect on extracellular MMP inducer expression. Material and Methods: Cultured human periodontal ligament cells were treated with varying concentrations (0.01-10 ng/mL) of interleukin-1beta at for 6, 12 and 24 h. Reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, gelatin zymography and western blotting were performed to measure the mRNA and protein levels of MMP-1, MMP-2 and extracellular MMP inducer. Results: Basal levels of mRNA and protein for MMP-1, MMP-2 and extracellular MMP inducer were detected in untreated human periodontal ligament cells. Interleukin-1beta significantly up-regulated the expression of MMP-1 and MMP-2 mRNA and protein (p < 0.05); however, the levels of mRNA and protein for extracellular MMP inducer were not significantly different (p > 0.05). In the culture medium, the concentration of MMP-1 was also increased significantly, butthe concentration of MMP-1 was not related to the concentration of extracellular MMP inducer (R-2 = 0.2538, p > 0.05). Conclusion: Interleukin-1beta up-regulated the levels of MMP-1 and MMP-2, but it did not alter the expression of extracellular MMP inducer. Expression of MMP-1 and MMP-2 might be elevated by interleukin-1beta and extracellular MMP inducer via two different signal pathways.