Morphometric evaluation of tissue-implant reaction associated with ALCAP and TCP bioceramics in vivo

The purpose of this investigation was to correlate the thickness of the fibrous capsule and the various histological components surrounding aluminum-calcium phosphate (ALCAP) and tricalcium phosphate (TCP) bioceramics at the subcutaneous (sc) and intraperitoneal (ip) implantation sites. The rational of conducting this investigation is to further elucidate the mechanisms of tissue-implant interaction, Thirteen Sprague-Dawley adult male albino rats were randomly divided into three groups. Animals in groups I and II (n = 5/group) were implanted at both ip and sc implantation sites with either ALCAP or TCP ceramics, respectively. Animals in group III (n = 3) were not implanted and served as the intact control for the comparative purposes. At 90 days postimplantation, the animals in all groups were euthanized (Ketamine/Zylazane) and the fibrous tissue surrounding the ceramic devices was retrieved. After routine histological processing, sections (5 mum) of tissue was stained with hematoxylin and eosin (H&E) and evaluated using light microscopy. With the exception of neutrophils, at both implantation sites, the fibrous tissues surrounding the TCP bioceramics demonstrated greater capsular thickness, more vascularity, and more macrophages, fibroblasts, and collagen than those surrounding the ALCAP ceramic. Data obtained from this investigation provided further insights into the differences in the tissue-implant responses of calcium-phosphate-based ceramics and the cellular composition of the fibrous tissue reaction found at sc and ip implantation sites.