Exploring The Protective Effect Of Schisandrae Chinensis Fructus On LPS/D-GalN Induced Acute Liver Injury And Its Mechanism Based On Cell Pyroptosis

Acute liver injury induced by lipopolysaccharide combined with D-Galactosamine(LPS/D-GalN)is a classic model that simulates human acute inflammatory liver injury.Even though there have been a great deal of studies on the occurrence and progress of acute liver injury,the specific molecular mechanism is not well understood.Schisandrae Chinensis Fructus has the effect of hepatoprotective,anti-inflammation and anti-oxidation,with the highest content of lignans,which is the main active ingredient in its biological functions.The study aimed to explore the hepatoprotective activity of Schisandrae Chinensis Fructus on acute liver injury provoked by LPS/D-GalN in mice and its mechanism based on cell pyroptosis.Firstly,the study screened the dose of silymarin,the positive control drug of LPS/D-GalN induced acute liver injury.It was found that intraperitoneal injection of LPS(10 μg/kg)/D-GalN(200 mg/kg)could reduce the survival rate of mice and cause liver inflammation.The dose of silymarin,80mg/kg,could significantly improve the survival rate of mice and reduce liver inflammation.Then,the hepatoprotective effect of Schisandrae Chinensis Fructus was investigated.Studies showed that Schisandrae Chinensis Fructus could improve the survival rate of ALI mice,reduce the liver index of model mice,improve the morphology of liver tissue cells,reduce the abnormal elevation of alanine aminotransf-erase(ALT)and glutamicoxalacetic transaminase(AST)in serum,and reduce the production of liver inflammatory factors TNF-αand IL-6.Schisandrae Chinensis Fructus showed a strong protective effect on acute liver injury induced by LPS/D-GalN in mice.Secondly,the protective mechanism of Schisandrae Chinensis Fructus on liver injury was investigated based on cell pyroptosis.The expression of pyroptosis-related proteins including caspase-1,nucleotide-binding oligomerization domain like receptor protein 3(NLRP3),apoptosis-associated speck-like protein containing a caspase-recruitment domain(ASC),Gasdermin D(GSDMD)etc.were studied in animal model of acute liver injury.The results showed that Schisandrae Chinensis Fructus could inhibit cell pyroptosis in acute liver injury.Besides,in the mouse macrophages RAW264.7 cell pyroptosis process induced by LPS and 5’-Adenylate tripHospHate(ATP)in vitro,the regulation effect of Schisandrae Chinensis Fructus lignans on cell pyroptosis was also verified.The results showed that lignans could inhibit the RAW264.7 cell pyroptosis,and the effects of Schisandrin B and Schisandrol A were more obvious.Due to the role of mitochondrial dysfunction caused by mitochondrial oxidative stress and decreased mitochondrial membrane potential(MMP)in the activation of NLRP3 inflammasome with the subsequent cell pyroptosis mediated by it,It was hypothesized that Schisandrae Chinensis Fructus may inhibit NLRP3 inflammasome mediated cell pyroptosis by inhibiting mitochondrial oxidative stress and increasing MMP,thus alleviating the inflammatory response and protecting liver injury.To verify this hypothesis,we studied the changes of oxidative stress index reactive oxygen species(ROS),lipid peroxide malondialdehyde malondialdehyde(MDA),and catalase(CAT),total-superoxide dismutase(T-SOD),glutathione(GSH),glutathione peroxidase(GSH-Px)based on the acute liver injury model,as well as the changes of mitochondrial ROS and MMP in the cell pyroptosis model.Results in vitro and in vivo have shown that improvement of mitochondrial function may be an important mechanism of Schisandrae Chinensis Fructus and its lignans in inhibiting cell pyroptosis and preventing acute liver injury.In summary,Schisandrae Chinensis Fructus can reduce the cell pyroptosis mediated by NLRP3 inflammasome activation by protecting mitochondrial function with inhibiting mitochondrial oxidative stress and maintaining the stability of MMP,thereby alleviating the inflammatory response and exerting a protective role on acute liver injury.This study revealed a new mechanism of Schisandrae Chinensis Fructus to protect LPS/D-GalN induced acute liver injury,and provided a theoretical basis for the development of new hepatoprotective drugs.