Tetrandrine suppresses lipopolysaccharide-induced microglial activation by inhibiting NF-κB pathway

Aim： Microglial activation has been implicated in many neurological diseases. In this study, we examined the effects of tetrandrine （TET）, a major pharmacologically-active compound of Chinese herb Stephania tetrandra S Moore on microglial activation. Methods： The microglia pretreated with or without TET were activated by lipopolysaccharide （LPS） in vitro. Nitric oxide （NO） release, superoxide anion （O2^-） generation, as well as TNF-α and interleukin-6 （IL-6） production by microglia were measured afterwards. Electrophoretic mobility shift assay was performed to determine whether NF-κB activity in microglia was affected by TET treatment. Results： We found that TET inhibited the LPS-induced activation of microglia by decreasing the production of NO and O2^-, consequently affecting the release of TNF-α and IL-6 in LPS-induced microglial activation. Such suppressive effect was accompanied by inhibiting transcription factor NF-κB activation. Conclusion： Our results suggest that TET might modulate LPS-induced microglial activation by inhibiting the NF-κB-mediated release of inflammatory factors.