Protective effects of endotoxin pretreatment on hepatic tissue in rats with endotoxemia

Objective To investigate the protective effects of endotoxin precondition on hepatic tissue in rats with endotoxemia.Method The models of rats with acute endotoxemia were produced by injecting LPS directly.Seventy-two male wistar rats were randomly divided into three groups:saline control group(N,n=24),lipopolysaccharide (LPS)-treated group(L,n=24),LPS pretreated group(P,n=24).Each group was divid-ed into four subgroups:saline control and lipopolysaccharide (LPS)-treated 2 h,4 h,6 h,12 h groups and LPS-pretreated 2 h,4 h,6 h,12 h groups.Rats in group P were first administered with introperitoneal injection of 0.25 mg/kg LPS,and after 24 hours,the rats were injected with 0.5 mg/kg LPS.Rats in group N and group L received with an equivalent amount of saline.After 72 hours,rats in group L and group P were intravenonsly injected with 10 mg/kg LPS,and rats in group N received with an equivalent amount of saline.Six rats were killed at 2,4,6 and 12 hours after injection of LPS in group L and P.The hvers were removed for detecting Toll like receptor-4 (TLR-4),nuclear factor-кB(NF-кB),tumor Necrosis Factor-apha(TNF-α)and malondialdehyde(MDA).The blood was drawn for detecting Alamine aminotmnsferose (ALT) and Aspartate aminotransferose (AST).The patho-logical changes of liver were also examined.Software SPSS13.0 was utilized to do ANOVA for statistical analysis.Results The rats exposed to LPS alone demonstrated an increase in TLR-4.NF-кB and TNF-α activity of the liver tissue.Incontrast.the rats exporsed 10 LPS prelreatment exhibited a significant decrease in TLT-4,NF-кB and TNF-α activity.The contents of TLR-4,NF-кB and TNF-α of LPS-treated 4 h groupwere,(38.76±0.67),170.82 ±31.40),293.16±49.49)and(6.263±0.351),significantly higher than those of the saline control group.The administration of endotoxin pretreatment reduced the indexes to(22.35±1.35),(135.55±26.44)and(234.23±44.96),respectively(P＜0.05).Conclusions TLR-4,NF-кB and TNF-α take part in the progress of hepatic injury in rats with endotoxemia.Endotoxin pretreatment can eliminate hepatic injury and protect the hepatic tissue by downmgulating the levels of TLR-4.NF-кB and TNF-α. Key words: Endotoxin; Endotoxemia; Pretrealment; liver injury; Toll like receptor-4