Osteogenic promotion by naringin through the PI3K/AKT/mTOR pathway-mediated activation of autophagy and inhibition of apoptosis.

Abstract

Osteoporosis is a common age-related metabolic bone disease closely associated with osteoblast dysfunction, abnormal apoptosis, and dysregulated autophagy. Naringin, a dihydroflavonoid compound mainly found in citrus fruits and various traditional Chinese medicinal herbs (e.g., Aurantii Fructus Immaturus and Rhizoma Drynariae), exhibits potential anti-aging and osteoprotective effects; however, its specific mechanism requires systematic elucidation. Network pharmacology analysis revealed that the core targets of naringin are significantly enriched in the PI3K/AKT signaling pathway, as well as pathways related to apoptosis and autophagy. Subsequent in vitro experiments demonstrated that naringin promotes osteoblast proliferation, differentiation, and mineralization; upregulates the expression of osteogenic markers; activates protective autophagy; and inhibits apoptosis. By employing the autophagy inhibitor 3-MA and the PI3K/AKT agonist 740Y-P to modulate PI3K/AKT/mTOR-mediated autophagy, we confirmed that the anti-apoptotic effect of naringin is dependent on the activation of autophagy. In vivo, naringin administration inhibited the excessive activation of the PI3K/AKT/mTOR pathway, enhanced autophagy, suppressed excessive apoptosis, ameliorated bone microarchitecture, and increased bone mineral density in ovariectomized mice. Our findings elucidate the mechanism by which naringin exerts its anti-osteoporotic effects through regulating the balance between autophagy and apoptosis, thereby providing a theoretical basis for developing naringin-based anti-aging strategies for bone protection.