The response of peritoneal macrophages after implantation of several ceramics as measured by the change of ectoenzyme activity.
The bioactive calcium phosphate ceramics with various calcium: phosphorus ratios: Ca/P = 1.67 (hydroxyapatite, HA), Ca/P = 1.6 and Ca/P = 1.5 (tricalcium phosphate, beta-TCP), the bioinert aluminium oxide ceramic (Al2O3) and the toxic calcium oxide ceramic (CaO) have been investigated with respect to their ability to activate peritoneal macrophages of NMRI-mice and with respect to their influence on the extracellular nucleotide degradation of these macrophages. Two weeks after the intraperitoneal injection of a suspension of ceramic particles in an isotone salt solution (phosphate-buffered saline = PBS), we observed that the peritoneal macrophages were only slightly activated into the responsive state, independent of the type of ceramic. 5'Nucleotidase (5'N) ectoenzyme hydrolyses adenosine monophosphate (AMP) and a decrease of its activity is a general biochemical marker of activated macrophages. This ectoenzyme activity was slightly reduced after ceramic implantation. The lacking rise of the extracellular diadenosine tetraphosphate (Ap4A)-catabolism by the macrophage ectoenzyme alkaline phosphodiesterase I (APD) demonstrated that the peritoneal macrophages did not completely reach the responsive state. After the implantation of calcium phosphate ceramics the extracellular adenosine triphosphate (ATP)-reduction was slightly diminished. After the implantation of tricalcium phosphate ceramic about 30% more peritoneal exsudate cells (PEC) were obtained from the peritoneal cavity than after injections of pure PBS (used as non-inflammatory control). Similar to the phenomena following the injection of thioglycollate (Tg, inflammation producing control agent) a slightly but not significantly increased proportion of pseudopodia-building cells was observed after the implantation of the ceramic with Ca/P = 1.6.
Otto
B
B
Biochemical Institute, Faculty of Medicine, Friedrich-Alexander-University, Erlangen, Germany.
Ogilvie
A
A
D015720:5'-Nucleotidase / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000537:Aluminum Oxide / Q000494:pharmacology; D000818:Animals; D017610:Calcium Compounds / Q000494:pharmacology; D002130:Calcium Phosphates / Q000494:pharmacology*; D002516:Ceramics / Q000494:pharmacology*; D015226:Dinucleoside Phosphates / Q000378:metabolism; D005260:Female; D008262:Macrophage Activation / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D010087:Oxides / Q000494:pharmacology; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D019736:Prostheses and Implants
D017610:Calcium Compounds; D002130:Calcium Phosphates; D015226:Dinucleoside Phosphates; D010087:Oxides; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D000249:Adenosine Monophosphate; C020733:diadenosine tetraphosphate; C485838:calcium phosphate, monobasic, anhydrous; D000255:Adenosine Triphosphate; C020243:calcium phosphate; C016538:lime; D015720:5'-Nucleotidase; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I; D000251:Adenosine Triphosphatases; C027201:ectoATPase; C485829:calcium phosphate, dibasic, anhydrous; D000537:Aluminum Oxide