Content Of Flagellin And Expression Of TLR5 In The Peripheral Blood Of The Patients With Sepsis

Acute lung inflammation culminating in acute respiratory distress syndrome (ARDS) is a major complication of gram-negative bacterial sepsis. The commonly held view is that bacterial lipopolysaccharide (LPS) released into the circulation activate interconnected inflammatory cascades in the lung,ultimately leading to diffuse alveolar damage. Whether additional bacterial toxins play roles in the development of acute pulmonary inflammation during gram-negative sepsis exist?Flagellin is a recently identified bacterial product that elicits Acute Pulmonary Inflammation in Sepsis response via toll-like receptor 5. The study was taken to detect the content of flagellin and expression of TLR5 at the mRNA level in the peripheral blood of patients with sepsis to discover the mechanism of ALI.MethodsDate from the American Colleague of Chest Physicians:Society of Critical Care Medicine Consensus Conference, Sepsis:SIRS plus a documented site (documented by positive culture for organisms form that site).Patients were classified into two groups: G- group, patients with sepsis infected by Gram negative bacilli(G- group,n=14) and G+ group, patients with sepsis infected by Gram positive bacilli (G+ group, n = 8). And 9 healthy people were chosen randomly as control.Systemic Inflammatory Response Syndrome(SIRS):Patient presents with two or more of the following criteria. 1.temperature>38.3℃or <36℃2.heart rate>90beats/minute 3.respiration>20/minute or PaCO2<32mmHg 4.Ieukocyte count>12×109/L,< 4.0×109/L or >10% immature cells. The content of flagellin was determined by ELISA .The peripheral blood mononuclear cells (PBMC)were isolated by the density gradient centrifugation. The total RNA of the PBMC was extracted by RNA BIOzol extract.The expression of TLR5 at the mRNA level in the peripheral blood was detected by semiquantitative RT-PCR. The significance among different groups was examined by t-test ResultsPlasma flagellin was not detected in G+ group and control group,while detected in G-group (6.636±5.147ng/ml). The expression of TLR5 at the mRNA level in G-group were significantly higher than in G+ group and control group. And no significant difference was found between G+ group and control group ( P >0.05).ConclusionFlagellin may play important roles in the happening and the development of ALI by activating TLR5.