A Study On The Change And Meaning Of Flagellin In Rat With Acute Lung Injury Induced By Sepsis

Recent investigations have demonstrated that flagellin can induce the expression of proinflammatory mediators, and that flagellin is a mediator of systemic inflammation, oxidant stress, and organ damage induced by gram-negative bacteria. How does flagellin change in rats with ALI caused by sepsis? Is there a relationship between the change of flagellin and the degree of ALI? This study was therefore undertaken to determine flagellin in serum, BALF and lung homogenate of rat after cecal ligation and puncture (CLP), and evaluate the relationship between flagellin concentrations and ALI induced by sepsis.MethodsA total of 120 Wistar healthy male rats were randomly divided into 2 groups including sepsis group (treated with CLP), Sham operated group (treated with only opening and closing the rats' abdomen without CLP). We monitored blood gas. Flagellin levels in serum, BALF and lung homogenate were determined at the time point of 2h, 4h, 6h, 12h, 24h and 48h after operation using enzyme linked immunosorbent assay (ELISA). We determined the wet/dry ratio (W/D) of lung tissue and observed the pathological changes of lung. Linear regression analysis was used to evaluate the relationship between flagellin concentrations and PaO₂ and W/D.ResultsSepsis-induced acute lung injury model of rat was successfully established. The partial pressure of oxygen in artery (PaO₂ ) in the sepsis group significantly decreased at the time point of 12 h after injury and reached the lowest point at the time point 48 h after injury. PaO₂ in sepsis group was significantly lower than in Sham operated group after operation 12h, 24h, 48h correspondingly (P<0.01). Flagellin concentration in the sepsis group was significantly higher than in the Sham operated group after operation 12h, 24h, 48h correspondingly(P <0.01). The difference of pathological changes of lung between sepsis and Sham operated group is significant. W/D in sepsis group was significantly higher than in Sham operated group after operation 12h, 24h, 48h correspondingly (P <0.01). Weobserved a statistically significant correlation between the flagellin concentrations and the levels of PaO2 and W/D(P <0.01).ConclusionThis study suggests that sepsis induced by CLP can lead to a marked elevation of flagellin, which might be associated with ALL...