Distribution of tenascin-X in different synovial samples and synovial membrane-like interface tissue from aseptic loosening of total hip replacement

The distribution of tenascin-X (Tn-X) was investigated in synovial samples from rheumatoid arthritis (RA), osteoarthritis (Oh) and knee injuries, and in synovial membrane-like interface tissue (SMLIT) from aseptic loosening o f total hip replacement (THR). An affinity purified rabbit antiserum agains t Tn-X was applied in avidin-biotin-peroxidase complex method. Double immun ofluorescence labeling was used to assess the spatial relationship of Tn-X and Tn-C. All samples showed Tn-X immunoreactivity. Strong staining appeal- ed in the lining and lining-like layers of RA and SMLIT samples, respective ly. An intensive immunoreactivity was also found in pannus tissue in RA, an d around multinucleate gaint cells and polyethylene wear debris in SMLIT. S taining intensity/extent varied significantly in different samples in the f ollowing rank order: SMLIT, RA, OA, knee synovium membrane. Double labeling revealed two patterns of Tn-X/Tn-C distribution, reciprocal and co-localiz ation. Our results suggest that Tn-X is an essential component of normal sy novial membrane, and that inflammatory mediators may increase local Tn-X pr oduction, Tn-X distribution is not always reciprocal to that of Tn-C.