Expression of vitronectin and its integrin receptors in the synovial membrane-like interface tissue from aseptic loosening of total hip replacement

Objective. To investigate expression of vitronectin (VN) and its integrin ( Int) receptors in synovial membrane-like interface tissue (SMLIT) in asepti c loosening of total hip replacement (THR), and the potential role of VN-In t interaction in production of collagenase-3. Methods. Avidin-biotin-peroxidase complex (ABC) staining was used to detect distribution of VN and Int alpha V, beta 3, and beta 5 subunits, Immunoflu orescence labeling with FITC and TRITC conjugated IgG was used to localize Int beta 3 subunit and matrix metalloproteinase (MMP-13) double positive ce lls in SMLIT. Results. Intensive VN immunoreactivity was found in the lining-like layers, sublining area, and endothelium of SMLIT, Statistical analysis of the VN s taining score revealed a significant difference between SMLIT and control s ynovial membrane. All 3 Int subunits appeared in the lining-like layers and sublining area, The Int beta 3 subunit was also detected in giant cells of SMLIT, Int beta 5 subunit staining was relatively weak and rarely found in vascular endothelium. Immunofluorescence labeling showed many double posit ive cells in the lining-like layer and sublining area of SMLIT. Conclusion, Expressions of VN and Int alpha V beta 3 and alpha V beta 5 are increased in SMLIT compared with that in OA synovial membrane. Int alpha V beta 3 engagement with VN might play a potential role in local MMP-13 prod uction in SMLIT.