Flavonoids of Herba Epimedii Enhances Bone Repair in a Rabbit Model of Chronic Osteomyelitis During Post-infection Treatment and Stimulates Osteoblast Proliferation in Vitro.

Flavonoids are the active component of the Herba Epimedii (H. Epimedii), which is commonly used in Asia. This study is to investigate the effect of H. Epimedii on bone repair after anti-infection treatment in vivo. The bioactive-composition group of H. Epimedii (BCGE) contained four flavonoids with the total content of 43.34%. Rabbits with chronic osteomyelitis in response to injection with Staphylococcus aureus were treated with BCGE of 242.70 mg/kg/day intragastrically after vancomycin-calcium sulphate treatment. Micro-computerd tomography (CT), morphology, blood biochemistry and osteocalcin levels were assessed for effect evaluation. In addition, the rat calvarial osteoblasts infected with S. aureus were treated with vancomycin and BCGE. Cell viability, alkaline phosphatase activity, bone morphogenetic protein 2, Runt-related transcription factor 2, osteoprotegerin, receptor activator of nuclear factor-κB ligand mRNA levels and protein expression were assessed. Our results indicated that BCGE promoted bone repair via increasing the bone mass, the volume of bone, promoting osteocalcin secretion after vancomycin-calcium sulfate treatment. BCGE enhanced the cell proliferation, by regulating bone morphogenetic protein 2, runt-related transcription factor 2, and osteoprotegerin/receptor activator of nuclear factor κ-B ligand mRNA and protein expression to maintain the balance between bone formation and bone resorption. Therefore, BCGE is a potential adjuvant herbal remedy for the post-infection treatment of chronic osteomyelitis.