Sesamin Ameliorates Lipopolysaccharide/D-Galactosamine Induced Fulminant Hepatic Failure By Suppression Of Toll-Like Receptor 4 Signaling In Mice

Objective:To investigate the potential effects and mechanisms of sesamin on LPS/D-GalN-induced fulminant hepatic failure in mice.Methods:1. In vivo, mice were randomly divided into six groups:blank control group, sesamin control group, model group and three concentrations of sesamin intervention groups. Mice were gavaged with different dosages of sesamin (10,30,100 mg/kg) every 8 h one time for three times with in 24 h before intraperitoneal injected with LPS(50 μg/kg)/D-GalN(800 mg/kg). After LPS/D-GalN challenge, the mortality was evaluated, serum ALT and AST activities were analyzed. The damage and apoptosis of the livers were evaluated by HE, TUNEL and IHC of Active-Caspase-3. The serum and hepatic expression of TNF-a were detected by ELISA and QRT-PCR. The protein expressions of MPO, ICAM-1, ECAM-1, TLR4, p-IκB, p-p38 were determined by Western blot.2. In vitro experiment, RAW264.7 macrophages were pretreated with sesamin 30 min prior to LPS stimulation. The TNF-α levels of the cell culture supernatants were determined by ELISA. The transcriptional activities of AP-1 and NF-κB were determined by luciferase reporter gene assay. Flow cytometry was used for detection the expression of TLR4 on the surface of macrophages.Results:1. Sesamin dose-dependent improved LPS/D-GalN-induced mice survival, reduced the activities of serum ALT and AST.2. Sesamin dramatically alleviated hepatocytes apoptosis and neucrosis in the liver of mice induced by LPS/D-GalN. The results of HE showed that sesamin obviously decreased LPS/D-GalN-induced liver necrosis areas of mice. TUNEL analysis indicated that Sesamin inhibited LPS/D-GalN-induced hepatocytes apoptosis. The tests of IHC demonstrated that sesamin restrained the expression of hepatic Active-Caspase-3, which induced by LPS/D-GalN.3. Sesamin inhibited LPS/D-GalN-induced recruitment of neutrophils, reduced the expressions of ICAM-1 and ECAM-1 in the liver of mice.4. Sesamin reduced LPS-induced production of TNF-a in serum, hepatic tissues and supernatants of RAW264.7 cells.5. In vivo and vitro experiments, sesamin inhibited LPS induced p38 MAPK and NF-κB activation and down-regulated the expression of TLR4 on the surface of macrophages.Conclusion:Sesamin protects mice from LPS/D-GalN-induced fulminant hepatic failure. The protection mechanism of sesamin may be through down-regulating the expression of TLR4, inhibiting the activation of p38 MAPK and NF-κB, and then decreasing the expression of TNF-a.