Role of hypoxia and interleukin-1beta in gene expressions of matrix metalloproteinases in temporomandibular joint disc cells.

The aim of this study was to test the hypothesis that hypoxia and interleukin-1 (IL-1)beta played a substantial role in gene expressions of matrix metalloproteinases (MMPs) in temporomandibular joint (TMJ) disc cells. The TMJ disc cells were isolated from rabbit TMJ, and cultured in Dulbecco's modified Eagle's medium (DMEM). The experiment was performed for 24 h in hypoxic (2% O2) and IL-1beta stimulated conditions. To examine the effect of hypoxia and IL-1beta on gene expression of MMPs and tissue inhibitors of metalloproteinase (TIMPs), we performed reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-RCR. The results showed that the combination of hypoxia and IL-1beta caused a significant increase of MMP-1, MMP-3, MMP-9 and MMP-13 mRNA (P < 0.05). Hypoxia caused a significant increase of MMP-2 mRNA (P < 0.05). The combination of hypoxia and IL-1beta caused a significant decrease of TIMP-3 compared to hypoxia (P < 0.05). These findings suggest that hypoxia and IL-1beta may contribute to the degradation or remodelling of the extracellular matrix (ECM) of the disc and may have a role in the pathogenesis of TMJ disorders.