The immunity effects of quorum sensing in the pulmonary infection in rats due to pseudomonas aeruginosa / 中华急诊医学杂志

ABSTRACT

Objective To investigate the immunity effects of quorum sensing in the pulmonary infection in rats due to Pseudomonas aeruginosa.Method(1)300 healthy,clean Sprague-Dawley rats were divided into 3 groups randomly:two different Pseudomonas aeruginosa(the wide-type Pseudomonas aeruginosa PAO1 and its double mutant PAO-JP2,in which the quorum sensing systems were defective,embedded in minute seaweed algiante beads which was made by an ejection set with an acuminate hole were inoculated to Sprague-Dawley rats to establish animal model of chronic pulmonary infection.The control group were dealed with the same methods using the sterile brine instead.(2)The levels of antibody IgG,IgM,IgG1,IgG2a to Pseudomonas aeruginosa in sera and cytokines including interferon-?(IFN-?),Interleukin-4(IL-4)in lung homogenate was measured at 3,7,14,28 days after infection.Results(1)The mortality in the PAO1-JP2-infected group(11.0%)was significantly lower than that of the PAO1-infected group(29.7%)and the control group(4.21%).(2) Compared with the PAO-JP2 group,during the early stages of infection(3 days after infection),the IFN-?level in lung homogenates was significantly higher;during the middle stages of infection(7 days after infection),the levels of IFN-?and IL-4 of PAO1-infected rats were significantly higher;In the later stages of infection(14 to 28 days after infection),levles of IFN-?,IgG2a were lower,while levels of IL-4,IgG,IgG1 were higher persistantly in PAO1-infected rats.Conclusions Quorum sensing system play an important role in pathogenesis and immunity effects of pseudomonas aeruginosa infection via modulating the expression of virulence factors and interfering with the immune system of hosts.