Protective Effect Of The Water Extract From Dioscorea Nipponica Makino Against Carbon Tetrachloride-induced Acute Liver Injury In Mice

Objective:To investigate the effect and possible mechanism of the water extracts from Dioscorea nipponica Makino(WEDN)against carbon tetrachloride(CCl4)-induced acute liver injury in mice.Methods:The medicinal plant of Dioscorea nipponica Makino was extracted by water following heating and reflux.The water extract was concentrated and then mix with 95%ethanol.After stewing,the deposition was separated and dried to produce,the crude extract for the experiment.The content of polysaccharide in extract was determined by ultraviolet(UV)-visible spectrophotometer with phemol-sulphuric acid method.In vivo study of CCl4-induced acute liver injury,sixty male KM mice were randomly divided into control,model,low-dose group(WEDN,50 mg/kg),middledose group(WEDN,100 mg/kg),high-dose group(WEDN,200 mg/kg),and positive control group(Silymarin,250 mg/kg)with ten mice in each group.The animals were adiminstrated with WEDN,silymarin and blank solvent for 7 days.Then,the mice were intraperitoneal injected with olive iol in control group,and intraperitoneal injected with 0.3%CCl4 olive iol solution in other groups to cause acute liver injury.The levels of AST and ALT in serum were detected,and the HE staining of liver section was carried out.The levels of MDA,SOD,GSH-Px and GSH in liver tissue were measured.The repression level of some proteins or genes including TNF-α,IL-6,IL-1β,MyD88,TLR4,NF-κB,iNOS,SOD1,SOD2,GST,HO-1,NQO1,Keap1 and Nrf2 associated with inflammation and oxidative stress were detected using Western blot and Real-time PCR assays.Results:The extraction rate of WEDN was 9.64%,in which the content of polysaccharide was 53.03 ± 0.70%by UV-visible spectrophotometry assay.The WEDN significantly reduced the serum levels of AST and ALT compared with model group(AST:113.40 ± 9.71 vs.39.60 ± 9.49 U/L;ALT:95.42 ± 11.64 vs.35.25 ± 9.93 U/L),markedly decreased MDA level(0.70 ± 0.08 vs.1.16± 0.20 nmol/mg protein),up-regulated SOD level(28.28±4.91 vs.21.15 ± 2.16 U/mg protein),and increased the levels of GSH(8.53 ± 1.04 vs,2.41±0.48 mg/g protein)and GSH-Px(73.34 ±12.21 vs.49.15 ± 8.68 U).HE staining showed that the inflammatory and the area of hepatic necrosis were reduced by WEDN compared with model group.In mechanism investigation,compared with model group,the expression levels of TLR4,MyD88,NF-κB,TNF-α,IL-1p and IL-6 were all down-regulated by WEDN.In addition,compared with model group,the protein levels of SOD1,SOD2,Nrf2,GST,NQO1 and HO-1 were all up-regulated by WEDN,and Keapl protein level and iNOS mRNA level were decreased.Conclusion:WEDN has protective effect against CCl4-induced acute liver injury in mice via adjusting TLR4/MyD88/NF-κB and Nrf2/Keapl signaling pathways to inhibit inflammation and oxidative stress.