Expression of OX40 in the livers of endotoxin tolerance rats and its significance / 中华传染病杂志

ABSTRACT

Objective To investigate the mechanism of endotoxin tolerance (ETT) through observing the expression of OX40 in liver tissues of ETT rats.Methods SD male rats were randomly divided into three groupsnormal group (n=6),acute liver failure (ALF) group (n=24) and ETT group (n=24).Lipopolysacharide (LPS) 0.1 mg/kg (ETT groups) or 0.9 ％NaC1 (ALF groups) was administered by five consecutive intraperitoneal injections at 24 h intervals,and at the sixth day,all animals were treated with intraperitoneal injections of D-galactosamine (D-GalN) 800 mg/kg and LPS 8 μg/rat.Blood and liver tissue were collected at 6,12,24 and 48 hours after the injection of D-GalN/LPS.The gene expression of OX40 in the liver was measured by reverse transcription-polymerase chain reaction (RT-PCR).The protein expression of OX40 was estimated by Western blot.The tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were determined by enzyme-linked immunosorbent assay (ELISA).The data analysis was performed by one-way ANOVA,lease significant difference (LSD) and Dunnett's T3 test.Results The expressions of TNF α and IL-6 were both significantly lower in ETT group compared to ALF group,but still higher than that of control group.The gene expressions of OX40 peaked at 12 hours and decreased gradually in ALF group.The gene expressions of OX40 were significantly lower in ETT group compared to ALF group (6 hF=5.027,24 hF=5.539,48 hF=5.011,all P＜0.05; 12 hF=36.688; P＜0.01),but still higher than that of normal group.The tendency of OX40 protein expression in ALF group was peaked at 12 hours and decreased at 24 hours.In ETT group,the expression of OX40 was lower,and the difference between ETT group and ALF group had statistical significance (6 hF=8.658,P＜0.05; 12 hF=34.611,24 hF=28.176,48 hF=16.747; all P＜0.01).Conclusions The level of OX40 is increased in ALF group,while the expressions of OX40,TNF-α and IL-6 are lower in ETT group,which suggested that OX40 may play an important role in the process of ETT.