To assess the distribution of fibronectins (FNs) and their integrin (Int) receptors in synovial membrane-like interface tissue (SMLIT) from aseptic loosening of total hip replacement (THR), and potential role of FN-Int interaction in the loosening process.
The alkaline phosphatase anti-alkaline phosphatase (APAAP) method was used to detect the distribution of FNs and their Int receptors in SMLIT and control samples. Double immunofluorescence labeling was used to reveal the different co-localizations.
Intensive FN staining appeared in the lining layers, sublining area, and vascular endothelium, while immunoreactivities for Int alpha 4, alpha 5, beta 1 subunits were detected in the lining and endothelial cells of SMLIT. Immunofluorescence labeling revealed Int alpha 5 and collagenase-1/collagenase-3 double positive cells in lining layers and sublining area of SMLIT.
Increased expression of FNs, Int alpha 4 beta 1 and alpha 5 beta 1 appeared in SMLIT compared with that in OA synovial membrane. FN-Int interactions may play a role in local collagenase production.