A tissue-implant reaction associated with subcutan implantation of alpha-tricalcium phosphate, dental ceramic and hydroxyapatite bioceramics in rats

Abstract

Calcium phosphate ceramics are among the more commonly used and biocompatible ceramics. Recently, we have synthesized a new calcium phosphate ceramic, alpha tricalcium phosphate (aTCP). The aim of this study was to assess the biocompatibility of this original, in our laboratory modified, newly synthesized aTCP ceramic, by carefully evaluating the inflammatory reaction of soft tissue in response to its subcutaneous implantation, and by comparing this result with the results of already widely used virtually non-toxic, non-immunogenic, and almost chemically inert dental (DC) and hydroxy apatite (HAP) ceramics. Implants (diameter 5x2 mm) of aTCP, DC and HAP were implanted into 12 adult male rats subcutaneously. At 2 weeks and 12 weeks post-implantation, the animals were euthanized and the tissueimplant reactions were analyzed histologically. Evaluation of routine stained sections (5 μm, hematoxylin & eosin) of the cutis and subcutis surrounding the aTCP, DC and HAP ceramics revealed the following: 1) all the ceramic devices had fibrous connective tissue capsules; 2) there were significant differences in the tissue - implant reactions based on the estimated time, while there were no differences in the tissue-implant reaction based on the type of ceramic material; 3) two weeks after implantation hyperemia and cellular proliferation were the most expressive results, while twelve weeks after implantation extensive angiogenesis and collagen fibers production were the prominent findings for all types of implanted calcium phosphate ceramics.

Podaci iz literature ukazuju da se kalcijum fosfatna keramika ubraja među najčešće korišćene i biološki najkompatibilnije keramičke materijale koji se danas primenjuju u medicini. U našoj laboratoriji sintetisana je nova vrsta kalcijum fosfatne keramike, alfa-trikalcijum fosfat (aTCP). Cilj ovog rada je bio da se proceni biokompatibilnost ovog, modifikovanog, novosintetisanog aTCP, putem pažljive procene inflamatorne reakcije mekog tkiva koja nastaje kao odgovor na njegovu subkutanu implantaciju i putem upoređivanja ovih rezultata sa rezultatima subku- tane implantacije dentalne keramike (DC) i hidroksiapatita (HAP), koji su ne-toksični, ne-imunogeni i skoro hemijski potpuno inertni. Kod 12 odraslih mužjaka Wistar pacova implantirani su subkutano implanti aTCP, DC i HAP (disk 5x2 mm). Na kraju 2. i 12. nedelje nakon implantacije, životinje su žrtvovane i reakcija tkivoimplant je analizirana histološki. Analiza rutinski obojenih (5 μm, hemotoksilin & eozin) isečaka tkiva kutisa i subkutisa koje se nalazilo oko implantiranog aTCP, DC i HAP, otkrila je sledeće: 1) svi keramički implanti bili su okruženi fibroznom kapsulom; 2) u odnosu na vreme posle implantacije, postojale su značajne razlike u tkivo-implant reakciji, dok u odnosu na vrstu keramičkog materijala, nisu postojale razlike u reakciji tkiva na implant; 3) za sve tri vrste implantirane kalcijum-fosfatne keramike, glavni nalaz u tkivu bio je, dve nedelje nakon implantacije, hiperemija i ćelijska infiltracija, dok nakon 12 nedelja prisutna intenzivna angiogeneza i stvaranje kolagenih vlakana.