[Effect of titanium particles and TNF-alpha on the gene expression and activity of MMP-1, 2, 3 in human knee joint synovial cells].

This paper is aimed to investigate the effect of titanium (Ti) particles and tumor necrosis factor alpha (TNF-alpha) on the expressions of MMP-1, 2, 3 in human synovial cells, so as to explore the possible mechanism of osteolysis post-operation of metal-on-metal total joint arthroplasty in human synovial cells induced by Ti particles. In vitro cell cultures, human synovial cells were treated by Ti particles and/or TNF-alpha. The total RNA was isolated at 2 hours after the treatment. The gene expression of MMP-1, 2, 3 was analyzed by Semi-quantitative Reverse-transcriptional PCR and quantitative real-time PCR. Cell supernatant was collected at 12, 24, 48 hours after the treatment and Gelatin zymography was performed to detect the activity of MMP-2. Compared to those in the control group (untreated), Ti particles and TNF-alpha increased the gene expression of MMP-1, 2, 3 respectively (P < 0.05), and the effect of combination of the two was even more significant (P < 0.01). The trend of activities of MMP-2 is similar with gene expression. Ti particles and TNF-alpha increased MMP-2 activities by 1.3 times and 1.5 times respectively (P < 0.05), and the combination of the two increased by 1.7 times (P < 0.01). Ti particles and TNF-alpha-induced the stimulation of MMP-1, 2, 3 expressions and MMP-2 activities in human knee joint synovial cells may be involved in aseptic loosening after metal-on-metal arthroplasty through increasing the degradation of bone matrix and declining of osseous support structure mechanics.