Calcification and identification of metalloproteinases in bovine pericardium after subcutaneous implantation in rats

The purpose of this study was to evaluate the influence of two anticalcific ation pre-treatments (chloroform/methanol and ethanol) and serum conditioni ng of glutaraldehyde-crosslinked bovine pericardium on the calcification de gree and the presence of gelatinase activities in a subcutaneous implantati on model in rats. Regarding calcification of the implants, glutaraldehyde c ontrol treatments showed a significatively higher calcification degree than pericardium treated with anticalcification reagents. Serum conditioning of glutaraldehyde treated tissues did not influence the calcification degree; moreover, no differences were found in these samples with the time of impl antation (30 and 90 days). On the other hand, anticalcification treatments resulted in a very significant decrease in the calcium content in the impla nted membranes. Gelatinase activities were detected by gelatin zymography in almost all the implanted samples. However, control tissues with and without serum conditi oning showed less gelatinase activities than those samples pre-treated with anticalcification treatments. Metalloproteinase (MMP-2) activity was detec ted in all the samples analyzed but a higher expression of MMP-9 was detect ed in those implants treated with chloroform/methanol and ethanol. Addition al gelatinase activities showing lower molecular weight than MMP-2 were als o detected in both anticalcification treated samples. The presence of these gelatinase activities is probably due to host cellular infiltrates and cou ld contribute to the biomaterial degradation. (C) 2001 Kluwer Academic Publ ishers.