A histological study of mineralised tissue formation around implants with 3D culture of HMS0014 cells in Cellmatrix Type I-A collagen gel scaffold in vitro

Abstract

We cultured HMS0014 Yub621b cells within a 3D collagen gel scaffold (Cellmatrix Type I-A) and aimed to study the fate and contribution of human bone-derived mesenchymal stem cells (MSCs) in the guided bone regeneration(GBR)-engineered tissue which has developed around the titanium (Ti) test dental implant (IP) in vitro. The light microscopy (LM) and transmission electron microscopy (TEM) results of the peri-IP tissue indicated that collagen fibrils of the Cellmatrix Type I-A gel were accumulated and fabricated to provide a 3D meshwork for proliferation and differentiation of the HMS0014 cells in the top (cell) layer; mineralisation of the GBR tissue had commenced since day 1 and became markedly deposited between days 7 and 14 of the experiment. TEM observation revealed sedimentation of cement line at the periphery of the interwoven Cellmatrix fibres and fibrils in the ECM scaffold of the GBR tissue; matrix vesicle-mediated and appositional collagen-mediated mineralisation were identified in the peri-IP ECM scaffold. The fine structure study of the plurimorphic osteoblast(Ob)-like osteogeneic cells demonstrated numerous membranous organelles related with vesicular trafficking, secretion and endocytosis in the cytoplasm; well-developed cytoskeleton networks and intercellular junctional complexes were also observed. The specimens on fluorescence immunohistochemistry (IHC) by confocal laser-scanning microscopy (LSM) showed the expression of LC3 and Cx43 associated with autophagic-lysosomal degeneration pathway and signal conduction mediated with gap junctions (GJS) in maintaining tissue homeostasis of the Ob-like cells which grew and degenerated in the 3D scaffold. Results from this in vitro study suggest that Ob-like HMS0014 cells actively regulate turnover of the peri-IP ECM to recapitulate the development and formation of osteoid tissue-engineered material which might contribute to augment osseointegration around the dental implant.