[Significance and role of increased expression of extracellular matrix metalloproteinase induced in the aseptic loosening of prostheses].

OBJECTIVE: To investigate the expression of extracellular matrix metalloproteinase induced (EMMPRIN) in the interface tissue, and explore the role of EMMPRIN in the aseptic loosening of prostheses. METHODS: Immunohistochemistry was performed to characterize the EMMPRIN-expressing cells at sites of interface tissue around aseptic loosened hip prostheses in 16 cases. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to study the existence of EMMPRIN mRNA in interface tissue samples. And it was followed up by computer assisted image analysis in order to detect the A values of their expression. Synovium of hip joint of 8 femoral neck fracture were in control group. RESULTS: Strong immunostaining of EMMPRIN was found in the macrophages and fibroblasts of lining-like layers and vascular endothelium of synovial membrane-like interface tissue around loosened prostheses. Expression of EMMPRIN was significantly higher in interface tissue than the control synovium (z=-3.252, P=0.001). RT-PCR of interface tissue samples disclosed the presence of EMMPRIN mRNA of 14 cases. In interface tissue, the A value of EMMPRIN increased significantly compared to control synovium (P<0.01). CONCLUSION: Over-expression of EMMPRIN up-regulates the production of matrix metalloproteinase (MMPs) in the interface tissue. And it can promote the bone destruction around prostheses. Thereby it may be one of methods to prevent and treat aseptic loosening of prostheses by repression the biology activity of EMMPRIN.