Tubeimoside I improves survival of mice in sepsis by inhibiting inducible nitric oxide synthase expression.

Sepsis is a disease with high mortality rate worldwide and inducible nitric oxide (iNOS) induced vascular hyporeactivity plays a key role in it. There is no effective drug to treat vascular hyporeactivity specifically. Tubeimoside I (TBM) is a triterpenoid saponin isolated from Rhizoma Bolbostemmatis. In this study, we found that 4 mg/kg TBM intraperitoneally injected 1 h before cecal ligation and puncture (CLP) partially improved survival, ameliorated mean arterial pressure (MAP) and enhanced vascular responsiveness to norepinephrine (NE) and KCl in wild-type septic mice. CLP activated TLR4-MyD88-NF-κB-iNOS pathway was also inhibited by TBM both in vitro and in vivo. However, iNOS gene knockout counteracted the protection provided by TBM. We conclude that TBM protects mice in sepsis by reducing excessive NO production through inhibiting the TLR4-MyD88-NF-κB-iNOS pathway. Our study suggests a possible therapeutic application of TBM in sepsis.