Immunohistochemical studies on the distribution of albumin, fibrinogen, fibronectin, IgG and collagen around PTFE and titanium implants

Time-dependent distribution of extracellular proteins (albumin, fibrinogen, fibronectin, collagen-I and IgG) in the interface zone between implant and soft tissue has been investigated utilizing a recently developed method. Commercially pure (c.p.) titanium and polytetrafluoroethylene (PTFE) implants were inserted in the abdominal wall of rats for 1, 6 and 12 weeks followed by a mild fixation, cryoprotection, rapid freezing in LN2-cooled propane, cryosubstitution and low-temperature infiltration with UV curing of the methacrylate LR-Gold. Before sectioning, the bulk part of the titanium was removed by an electrolytical dissolution technique (electropolishing), while the PTFE implants were removed by a fracture technique. Employing a cryosubstitution method combined with postembedding immunohistochemistry, a light microscopic analysis was allowed. The selected proteins had an apparently varying distribution in the implant-close tissue and their distribution changed during the follow-up period. There was also a difference in the distribution pattern for each protein around titanium and PTFE implants. Insertion of the c.p. titanium implants elicited an inflammatory reaction in many respects similar to a normal wound healing response, while the PTFE implants caused a more pronounced, persistent inflammation.