Bone proliferation in osteoporotic experimental animals using alginate-pullulan-bioactive glass‑gold nanoparticles composite

In the present study, scaffold composites based on alginate-pullulan-bioactive glass‑gold nanoparticles were orthotopically implanted in an experimental model of delayed bone union, in rats, given by a metabolic pathology, namely osteoporosis. Differences between treated and untreated groups were observed and the efficacy of our biomaterial was evaluated by applying micro-CT imaging, together with histological evaluation of the osteoporotic animals with sub-critical bone defects, at 30 and 60 days. Osteoporosis was successfully induced by ovariectomy in 9-month-old rats, confirmed by micro-CT and histopathological analysis. A secondary complication from a cortical bone defect was further induced to study bone proliferation in such a delayed environment. The studied composite presents osteointegration and angiogenesis properties at 60 days post-implantation in the osteoporotic animals. These results are given by the micro-CT analysis in which higher bone mineral density and bone volume fraction were observed, alongside histopathology, stating a lack of tissue necrosis and inflammatory reaction and the presence of new woven islands within and around the implanted biomaterial. This is the first endeavor to treat cortical bone defects in osteoporotic animals using scaffold biopolymers containing bioactive glass‑gold nanoparticles instead of cement.