Effects of gold nanoparticles and apricot seeds on bone healing in New Zealand rabbits

Objectives: Suboptimal osseointegration of implant materials is linked to oxidative stress and compromised bone regeneration. Gold nanoparticles (Au NPs) function as anti-inflammatory and osteogenic agents, promoting bone growth by reducing cell damage and enhancing cellular activity. Apricot seeds contain amygdalin, a natural antioxidant and osteogenic substance. This study aimed to evaluate the impacts of Au NPs and apricot seed extract on bone healing in a rabbit model. Methods: Twelve adult male New Zealand white rabbits were assigned to three groups: untreated (control), Au NPs treated, and apricot seed treated groups. Six holes were surgically drilled in the tibiae (right/left) of each animal. Each hole was injected with 0.3 mL of Au NPs or apricot seed liquid extract. Histological analysis was performed after 7 and 14 days of healing using hematoxylin and eosin (H&E)-stained bone samples, which were cut around the holes in all test animals. Light microscopy and S-EYE 2.0 software were used to count blood vessels, osteoblasts, osteocytes, and bone marrow spaces. Results: Local application of apricot seeds and Au NPs decreased vascularization and bone marrow spaces, and stimulated bone-forming cells, where Au NPs were more effective. Treatment with Au NPs significantly lowered the number of blood vessels after 14 days to the smallest value (2.6 ± 0.96) recorded under all treatments. By day 14, the numbers of osteoblasts (45.1 ± 4.36) and osteocytes (60.0 ± 7.71) were significantly higher under treatment by Au NPs compared with the control. Conclusion: Au NPs and the natural agent apricot seed extract enhanced osteoblasts and osteocytes in a rabbit model, and could potentially promote bone regeneration. However, these observations should be interpreted cautiously considering the limitations of this study, such as its retrospective design and single-center sample. These findings are an essential preliminary clinical step required to justify future human studies.