SOCS-1在内毒素血症及耐受小鼠肝组织中的表达变化及意义

Significance of SOCS-1 expression changes in the liver of endotoxemic mice and endotoxin-tolerant mice

目的:观察内毒素血症及内毒素耐受模型小鼠对LPS刺激的反应性,以及肝组织中SOCS-1表达的变化,试图从机体水平探讨SOCS-1与内毒素耐受状态之间的关系.方法:通过脂多糖(LPS)预处理建立内毒素血症及内毒素耐受动物模型,并与对照组进行比较.分时点用酶联免疫吸附试验(ELISA)检测细胞培养液中TNF-α水平,逆转录聚合酶联反应(RT-PCR)检测肝组织中TNF-α mRNA的表达水平以及肝组织中SOCS-1 mRNA的表达,并观察肝组织病理改变及超微结构改变,免疫组织化学检测SOCS-1在肝脏的表达.结果:在LPS刺激后,LPS组血清TNF-α水平、TNF-α mRNA、SOCS-1 mRNA均在1h开始升高,至3h时达到峰值,随后又逐渐下降正常水平;PBS组血清TNF-α水平及TNF-α mRNA表达几乎没有明显变化,且无SOCS-1 mRNA表达,与LPS组比较有统计学意义(P<0.01);但是耐受组(ETT)的3h血清TNF-α水平较非耐受组(NETT)低(693.38ng/L±95.2ng/Lvs1110.24ng/L±164.33ng/L,P<0.01);3h肝组织TNF-α mRNA表达峰值较NETT组低(97.96±19.67vs139.14±31.17,P<0.05);而肝组织SOCS-1 mRNA表达峰值较NETT组高(91.58±12.94vs52.82±6.96,P<0.01);肝组织可见脂肪变性、坏死等病理改变,超微结构表现为Kupffer细胞激活,吞噬功能增强;免疫组织化学可见肝组织中SOCS-1的表达.结论:内毒素耐受状态下,肝组织中的SOCS-1 mRNA表达却明显增强,肝组织中的SOCS-1 mRNA表达、Kupffer细胞的激活以及机体的内毒素耐受状态三者间可能有着紧密的联系.

AIM：To investigate SOCS-1 （suppressor of cytokine signaling-1） expression changes in the liver of endotoxemic mice and endotoxintolerant mice and to explore the relationship between SOCS-1 expression and endotoxin tolerance.METHODS：The mouse models of endotoxemia and endotoxin tolerance were established by lipopolysaccharide （LPS） pretreatment.At different time points after LPS pretreatment,the level of serum TNF-α was detected by enzymelinked immunosorbent assay （ELISA）,the expression levels of TNF-α and SOCS-1 mRNAs in the liver were detected by reverse transcriptionpolymerase chain reaction （RT-PCR）,the pathological and ultrastructural changes in liver tissue were observed,and SOCS-1 protein expression in liver tissue was detected by immunohistochemistry.RESULTS：After LPS stimulation,the levels of serum TNF-α and hepatic TNF-α and SOCS-1 mRNAs began to increase at 1 h,peaked at 3 h,and then decreased gradually to the normal level.In contrast,serum TNF-α and hepatic TNF-α mRNA levels showed no significant changes in mice treated with PBS.No SOCS-1 mRNA expression was detected in control mice （P 0.01）.At 3 h,serum TNF-α and hepatic TNF-α mRNA levels were significantly lower in endotoxintolerant mice than in endotoxin-intolerant mice （693.38 ng/L ± 95.2 ng/L vs 1110.24 ng/L ± 164.33 ng/L,P 0.01;97.96 ± 19.67 vs 139.14 ± 31.17,P 0.05）,while hepatic SOCS-1 mRNA level was significantly higher in endotoxin-tolerant mice than in endotoxin-intolerant mice （91.58 ± 12.94 vs 52.82 ± 6.96,P 0.01）.Pathological and histological changes in the liver of endotoxemic mice included fatty degeneration and necrosis,while the major ultrastructural change was presence of activated Kupffer cells whose phagocytic function was enhanced.Hepatic SOCS-1 protein expression could be detected by immunohistochemistry.CONCLUSION：SOCS-1 mRNA expression in liver tissue is enhanced markedly in endotoxintolerant mice.Close associations are noted among hepatic SOCS-1 mRNA expression,Kupffer cell activation and endotoxin tolerance.