Effects of alkaloids from Sophora flavescens on osteoblasts infected with Staphylococcus aureus and osteoclasts.

Chronic osteomyelitis is primarily caused by infection with Staphylococcus aureus (S. aureus). Antibiotics are commonly administered; however, it is a challenge to promote bone healing. The aim of this study was to investigate the in vitro effects of alkaloids from the herbal remedy Sophora flavescens (ASF) on rat calvarial osteoblasts (ROBs) infected with S. aureus and healthy osteoclasts. Cell proliferation and alkaline phosphatase, interleukin-6, and tumour necrosis factor-α activity was measured in infected ROBs; tartrate-resistant acid phosphatase was evaluated in osteoclasts via enzyme-linked immunosorbent assay. The mRNA and protein expression levels of bone morphogenetic protein 2, runt-related transcription factor 2, osteoprotegerin, and receptor activator of nuclear factor kappa-B ligand were assessed in infected ROBs through reverse transcription-polymerase chain reaction and western blotting analysis, respectively. Results indicated that ASF increased the viability of uninfected ROBs and infected ROBs treated with vancomycin via regulation of bone morphogenetic protein 2, runt-related transcription factor, osteoprotegerin, and receptor activator of nuclear factor kappa-B ligand mRNA and protein expression levels. In addition, the secretion of the inflammatory factor tumour necrosis factor-α was decreased and alkaline phosphatase activity was increased, inhibiting the viability of osteoclasts and tartrate-resistant acid phosphatase activity. Therefore, the herbal remedy ASF has potential as a new treatment for chronic osteomyelitis.