Strontium-Doped Hydroxyapatite Incorporated With Naringin for Osteoporosis Treatment

Osteoporosis is a highly prevalent systemic skeletal disease and a major risk factor for bone fractures. With the increase in population aging worldwide, the prevalence of osteoporosis has also increased. Nevertheless, there are unmet treatment demands for osteoporosis. Strontium plays a crucial role in bone biomineralization. Naringin is a flavanone glycoside with antiosteoporosis effects. Accordingly, this study synthesized strontium-doped mesoporous hydroxyapatite (Hap-Sr) particles and combined them with naringin (NHap-Sr) for use in osteoporosis treatment. Specifically, mesoporous Hap particles were doped with Sr at various molar ratios (10%, 20%, and 30%) through coprecipitation and then combined with naringin (NHap-Sr). These particles were characterized using X-ray diffractometry, transmission electron microscopy, and Zetasizer analysis. Thermogravimetric analysis was conducted to determine the naringin loading efficiency. Various cell models were used to evaluate the potential cytotoxicity and effects of NHap-Sr on bone turnover markers. The results indicated that Ca²⁺ ions were replaced with Sr²⁺ ions, expanding the Hap crystal lattice. Moreover, Hap-Sr20% was the optimal sample for the formation of a mesoporous structure with a particle size of 740-1600 nm and a naringin loading efficiency of 8.5%. NHap-Sr20% upregulated the mRNA expression levels of alkaline phosphatase, osteocalcin, osteoprotegerin, and receptor activator of nuclear factor kappa-B ligand in osteoblast-like cells without imposing cytotoxic effects or impairing mitochondrial membrane potential, demonstrating its ability to promote bone formation. Overall, combining Sr-doped Hap and naringin is a promising osteoporosis treatment strategy.