Effect Of TNF-α To TLR2and TLR4’s Expression In The Alveolar Macrophages In Rat With Ventilation Induced Lung Injury

OBJECTIVE To observe the effect of TNF-α to TLR2and TLR4’sexpression in the alveolar macrophages in rat with ventilation induced lunginjuryMETHOD36SD rats were randomly divided into control group (C group, n=18), TNF-α stimulate group (T group, n=18), and then randomly assignedeach group to three subgroups (CA group, TA group breathed autonomously,n=6; CS group, TS group breathed normal tidal volume, VT=7ml/kg, n=6; CLgroup, TL group breathed high tidal volume, VT=40ml/kg, n=6). Group Cinjected nothing from tail intravenous after spontaneously breathed4h afterintubation, T group injected TNF-α at10μg/kg from tail intravenous aftermechanically ventilated. Spontaneously breathed30minutes after tailintravenous injection. HE staining for observing morphological manifestation.Transmission electron microscopy for observing ultrastructure of rat macrophages. ELISA assay TNF-α, IL-1β, IL-6, IL-10expression in serum andbronchoalveolar lavage fluid (BALF). real time PCR detected the TLR2，4、NF-κB、MyD88mRNA expression in rat alveolar macrophage. Western blot andimmunofluorescence cytochemistry detected protein expression in rat alveolarmacrophage.RESULTS (1)The rat model of ventilation induced lung injury was createdsuccessfully.(2)The ratio of W/D in group L is higher than that in group S and A,P <0.05. and there is no obvious difference between group TL and CL, p﹥0.05.Tissue in group A express no obvious congestion, edema. In group S could see asmall amount of inflammatory cell infiltrated in lung tissue, and the tissueexpressed mild congestion, edema. In group L, the structure of alveolar wasdamaged, the alveolar walls and pulmonary interstitial contains a large numberof neutrophil and RBC, the pulmonary interstitial is edema and broadeningobviously, hyaline membrane formation on the alveolar surface. In group L,pseudopodia of macrophages was obviously increased, and also phagosomeand lysosome increased, we can also see lysosome emptying.(3) Group T isapparently than that of group C.TNF-α, IL-1β and IL-6expressed significantlyhigher in serum and BALF in group L and group S compared with group A, P<0.05. While IL-10expressed higher in group L compared to group A, P<0.05,compared to group A, it had no significantly difference in group S, p﹥0.05.(4) TLR2，TLR4, MyD88,NF-κB mRNA expressed higher in group L andgroup S compared with group A, P <0.05,and the increased extent of group T islarger than group C, P <0.05. TLR2，TLR4, MyD88,NF-κB protein expressedhigher in group L and group S compared with group A, P <0.05,and theincreased extent of group T is larger than group C, P <0.05, consistent with themRNA expression.(5) The expression level of NF-κb, MyD88in macrophage cells is positively correlated with the expression of TLR2and TLR4.CONCLUSION Both TLR2and TLR4participate in the immune responseof macrophages to mechanical ventilation and TNF-a stimulating. They adjustthe release of cytokines by stimulating the signal transduction pathways whichdependent of MyD88, to effect the nature of the macrophage immune response.TNF-a is the key priming factor in the process of ventilation induced lunginjury.TNF-a is one of the factors that regulate the expression of TLR2,4in alveolarmacrophages in ventilation induced lung injury.NF-κB played a pivotal role in the process of signal transduction of ventilationinduced lung injury...