[Influence and role of expression of extracellular matrix metalloproteinase inducer and matrix metalloproteinase 9 in aseptic loosening of prosthesis].

OBJECTIVE

To observe the expressions of extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase 9 (MMP-9) around the prosthesis, and to study the relationship between the expressions of EMMPRIN and MMP-9 and osteolysis around prosthesis.

METHODS

Interface tissues were obtained at three Delee-Charnley acetabular sections and seven Gruen femur sections from 8 cases (8 hips) undergoing revision after total hip arthroplasty between February 2010 and January 2012, and were divided into osteolysis group and non-osteolysis group based on preoperative X-ray film and intraoperative observation; the tissues from another 8 patients with osteoarthritis undergoing total hip arthroplasty as the control group. The immunohistochemical staining and RT-PCR assays were used to determine the expressions of EMMPRIN and MMP-9. The correlation between the positive cells and the severity of osteolysis were analyzed and compared.

RESULTS

Histological examination showed that many macrophages, multinucleated giant cells assembled in the membrane of osteolysis zone, but many fibroblasts and synovial cells in non-osteolysis zones. EMMPRIN and MMP-9 positive cells and gene expressions were observed in every group. The percentage of positive cells and gene expression of EMMPRIN and MMP-9 in osteolysis group were significantly higher than those in non-osteolysis and control groups (P < 0.05), but no significant difference was found between non-osteolysis group and control group (P > 0.05). The percentage of positive cells of EMMPRIN in zone III of acetabular was higher than that in zone I and zone II of revision hip (P < 0.05), but no significant difference between zone I and zone II (P > 0.05). The percentage of positive cells of MMP-9 in zone I and zone III was significantly higher than that in zone II of revision hip (P < 0.05), but no significant difference between zone I and zone III (P > 0.05). The expression of EMMPRIN from high to low in order was zones 1, 7, 4, 2, 3, 5, and 6 at femur; the values of zones 1, 7, and 4 were significantly higher than those of zones 2, 3, 5, and 6 (P < 0.05), but no significant difference among zones 1, 7, and 4, and among zones 2, 3, 5, and 6 (P > 0.05). The expression of MMP-9 from high to low in order was zones 1, 7, 4, 2, 3, 6, and 5 at femur; the values of zones 1 and 7 were significantly higher than those of zones 4, 2, 3, 6, and 5 (P < 0.05), and the values of zones 4 and 2 were significantly higher than those of zones 3, 6, and 5 (P < 0.05), but no significant difference between zone 1 and zone 7, between zone 4 and zone 2, and among zones 3, 5, and 6 (P > 0.05).

CONCLUSION

The expressions of EMMPRIN and MMP-9 have certain coherence. The over-expressions of EMMPRIN and MMP-9 may be one of the key points of inhibiting bone reconstruction and bone resorption at bone-implant interface under the stimulation of wear debris.