Objective This study aimed to investigate the effect of splenic CD11clow CD45RBhigh dendritic cell (DC)derived from endotoxin tolerance (ET)mice on the expression of zinc finger protein A20 in acute liver failure (ALF)and to clarify the possible mechanism.Methods ET mice were modeled. CD11clow CD45RBhigh DC were isolated from spleen by magnetic activated cell sorting (MACS).One hundred and twenty-six healthy male BALB/c mice were randomly divided into four groups:control group (group A,n=6),ALF group (group B,n =40),normal CD11clow CD45RBhigh DC-treated group (group C,n=40),ET-CD11clow CD45RBhigh DC-treated group (group D,n=40).Mice in group B,C and D were injected with D-galactosamine (D-GalN)600 mg/kg and lipopolysaccharides (LPS)10 μg/mouse.Mice in group A were given the same volume of normal saline (NS).Half an hour after the D-GalN/LPS injection,mice in group C were treated with splenic CD11clow CD45RBhigh DC derived from normal mice (1 ×10 6/mouse,0.2 mL/mouse).Mice in group D were treated with splenic CD11clow CD45RBhigh DC derived from ET mice (1 × 10 6/mouse,0.2 mL/mouse).Mice in group A and B were given the same volume of 0.9% NaCl solution (0.2 mL/mouse).Alanine aminotransferase (ALT)and aspartate aminotransferase (AST)levels were measured at each time point.Liver histopathological changes were confirmed by hematoxglin and eosin methods.Expressions of tumor necrosis factor-α (TNF-α),nuclear factor-kappa B (NF-κB),and zinc finger protein A20 were measured by reverse transcriptase polymerase chain reaction(RT-PCR)and Western blot.One-way analysis of variance was used to compare means between groups.Normal distribution and homogeneity of variance were tested.LSD test was conducted in patients accorded with homogeneity of variance.Results ALT and AST levels increased 2 h after modeling in group B and peaked at 24 h,which were significantly higher than groups A (t = 31 .00, 11 .52,both P <0.05).ALT and AST levels also increased after 2 h after modeling and peaked at 24 h in group C and group D,which were both significantly higher than group B (t =14.60,26.43,both P <0.05).The mRNA levels and protein expressions of TNF-αand NF-κB in group B increased gradually and peaked at 12 h after D-GalN/LPS injection.Compared to that of group A,the differences were both statistically significant (t = 427.58,122.42,179.35 ,165 .98,all P < 0.05 ).The mRNA level and protein expression of zinc finger protein A20 in group B decreased gradually and reached the minimum at 12 h after D-GalN/LPS injection,which was statistically different compared to group A (t = 90.80, 160.43,both P <0.05).On the contrary,the levels of zinc finger protein A20 in group C and D increased gradually and peaked at 12 h after D-GalN/LPS injection.The expression level of zinc finger protein A20 in group D was significantly higher than group C (t = 11 .21 ,24.80,both P < 0.05 ).Conclusion Treatment of splenic CD11clow CD45RBhigh DC derived from ET mice contributes to liver protection against D-GalN/LPS-induced ALF.