Chrysin Exhibits Bone‐Protective Effects Through Osteoclastogenesis Inhibition: In Vitro and In Vivo Evaluation in RAW 264.7 Murine Macrophages and Sprague–Dawley Rats

Bone is a metabolically active tissue that is constantly being reformed and resorbed by osteoblasts and osteoclasts. Abnormal increases in osteoclast activity can lead to bone deterioration. This study investigated the potential beneficial effects of chrysin on osteoclast formation in RAW 264.7 murine macrophages and bone health in Sprague-Dawley rats. Tartrate-resistant acid phosphatase (TRAP) staining was conducted to determine the effect of chrysin on osteoclast differentiation. Quantitative polymerase-chain reaction, western blotting, and immunofluorescence were conducted to determine the molecular mechanism of chrysin in osteoclasts. Sprague-Dawley rats were fed a diet of 50 mg/kg chrysin from postnatal Day 7 until 22. On Day 130, the rats were euthanized, and their tibiae were extracted and assessed by micro-computed tomography (microCT). Chrysin reduced the number of TRAP-positive osteoclasts formed by inhibiting nuclear factor κB (NFκB) nuclear translocation. Crucial genes involved in the activation of osteoclasts were further down-regulated. Chrysin significantly increased the area, volume, and segmented bone density of the midpoint of the tibiae. The findings suggest that chrysin inhibits osteoclastogenesis via the inhibition of the NFκB signaling pathway. Chrysin further induced moderate improvements in bone health parameters. These findings suggest chrysin may exert bone-protective effects by inhibiting osteoclasts.