This ultrastructural investigation deals with the mechanism of calcification which occurred after beta-phase tricalcium phosphate ceramics (
Synthograft™) were subcutaneously administered to rats.
Experimental animals were 50 male Wistar rats.Granules of
Synthograft™ were implanted in the subcutaneous tissue of rats. The rats were sacrificed 2, 4, 8, 16 and 24 weeks after implantation. Subsequently, nondecalcified ultrathin sections were prepared in accordance with the conventional method and were observed with a transmission electron microscope.
Two weeks after implantation,
Synthograft™ was surrounded by degenerative and inflammatory cells. Occasionally, macrophages phagocytosed the test materials. From 4 weeks postoperatively, osmiophilic, amorphous electron density structures deposited on the surface of the test materials. Especially 8 weeks after implantation, these structures were also observed in the porous spaces which could be found between electron dense
Synthograft™. Calcium and phosphorus were detected in these structures by energy dispersive X-ray microanalysis. However, these structures did not increase with the passage of time.
It is concluded that
Synthograft™ may not initiate dystrophic calcification but does cause initial calcification.
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