The Up-regulated Expression Of S100A8/A9in Monocytes And Macrophages And Its Role In Sepsis

ObjectiveTo examine the expression of S100A8/A9in monocytes and macrophages in sepsis,and to assess its association with serum level of pro-inflammatory cytokines andinflammation damages.MethodsThe blood samples were obtained from21patients with sepsis, which were admittedto the Intensive Care Unit in our hospital during January2012to December2012. Thenormal controlled group of16cases was set up as contrast. The expression of S100A8/A9was determined by flow cytometry in peripheral blood monocytes. LPS was injected intoabdominal cavity to built mouse model of sepsis. Peritoneal macrophages and liver tissuewere collected at24hours. The mRNA levels of S100A8, S100A9, TNF alpha, and IL-6were measured with Real-time PCR. The expression of S100A8/A9in liver was examinedby using immunohistochemistry.Results（1）The expression of S100A8/A9in monocytes were significantly higher in sepsispatients compared with the healthy controls (P<0.001).（2）The mRNA levels of S100A8, S100A9, and IL-6were higher in sepsis groupthan that in control group respectively (P<0.01). IL-6mRNA level was significantlycorrelated with S100A8mRNA and S100A9mRNA.（3）Hepatic inflammation was found in septic mice by H&E staining.Immunohistochemical analysis further revealed that S100A8/A9protein levels wereelevated in septic mice. Conclusions（1）Up-regulation of S100A8/A9on monocytes and macrophages may be a startsep of inflammation in the early phage of sepsis.（2）S100A8/A9may be an effective inducer of pro-inflammatory cytokines.（3）S100A8/A9may be involved in hepatic inflammation and damages duringsepsis.