Histological examination of the biocompatibility of polyethylene glycol terephthalate in a rat in vivo bone model

Objectives: The purpose of the study was to examine histocompatibility of polyethylene terephthalate (PET) fibers with bone tissue and its usability as a bone substitute. Materials and methods: Twenty male Wistar rats were divided into four groups equal in number. The proximal ends of the right hind tibia bones were drilled and PET thread ball fibers (PET, Advansa SaSA) were placed into 0.5 cm(2) holes. The left hind tibias (controls) were subjected to the same drilling procedure but were left untreated for natural healing. The four groups of rats were sacrificed after 2, 4, 6, and 8 weeks, respectively, and the hind tibias were removed for histologic examination. Results: There was an increased number of bone tissue cells surrounding PET fibers, which were similar to those of control specimens with respect to number and morphological features. Formation of fibroblasts and osteoblasts was at the highest level within the first two weeks. Giant cell formation was observed in all PET groups, but was larger in number in two- and eight-week groups. At 4, 6, and 8 weeks, osteoid tissue produced by osteoblasts was seen in some areas around the fibers without any formation of fibrous tissue. No signs of biodegradation of PET fibers were observed under light microscopy. Conclusion: The presence of osteoblasts, osteocytes, osteoids, and calcified new bone tissue around PET fibers suggests that PET has osteoconductive properties. In order to be used as a bone substitute, further studies are required on its biochemical and interaction properties.