Protective Effects Of PA-MSHA On Lung Injury In Septic Mice

ObjectiveMurine septic model in the experiment was established through cecal ligation puncture(CLP).We used PA-MSHA treatment before CLP and after CLP.We examined the serum TNF-α 、 IL-6 、 IL-10 and TGF-β concentration of sepsis rats,investigated the changes of TLR4 expression and adjust the proportion of T cells(TREG cell)in peripheral blood monocytes.We also detemined the expression of TLR4 m RNA and observed the pathological changes in lung tissues in different time intervention of PA-MSHA.The experiment was to investigate the effects and the possible mechanism of PA-MSHA on acute lung injury in septic rats.Methods120 SD rats of healthy grade,are weighed 250 ± 25 g.The total rats were randomly divided into sham operation group(SC group,N=30),sepsis group(CLP group,N=30),PA-MSHA treatment before CLP(A group,N=30),PA-MSHA treatment after CLP(B group,N=30).Murine septic model was established through cecal ligation puncture(CLP).Ten animals in each group were sacrificed at 12,24 and 36 h after operation,and blood was collected to examine serum TNF-α、IL-6、IL-10 and TGF-β concentration;the lung tissue samples were collected to detemine the expression of TLR4 m RNA by real-time PCR approach;the pathological changes in lung tissues were observed with light microscopy after HE staining;flow cytometry was used to investigate the changes of TLR4 expression on peripheral blood monocytes and analyze the proportion of CD4+CD25+Foxp3+T cells in peripheral blood cells.ResultsCompared with group CLP and group B,in group A: it can reduce the pathological injury in sepsis rats lung and the pathological score decreased significantly after 12 h and24h 36h(P<0.01,P<0.01,P<0.05).The serum TNF-a and IL-6 concentration were significantly lower(P<0.01)after12h、24h、36h of the operation,but IL-10 and TGF-βconcentration were significantly higher(P<0.01).The expression of TLR4 in peripheral blood mononuclear cells and the expression of TLR4 m RNA were markedly decreased(P<0.01)after 24 h of the operation.And the pulmonary pathological scores were related to the expression of TLR4 m RNA in sepsis rats lung Y=3.27+1.36 X,r=0.732,P<0.01。).Also the proportion of TREG cells in peripheral blood cells was markly improved in group A(P<0.01),but there was no statistic difference between group B and CLP group(P>0.05).ConclusionWhen treated PA-MSHA before CLP,it can reduce acute lung injury in septic rats.The mechanism may be related to increase the proportion of TREG in peripheral blood cells,which leads to the release of IL-10 and TGF-β and other anti-inflammatory factor.On the other hand,it can reduce the expression of TLR4 receptor in immune cells on the cell membrane,inhibit TLR4-NF-κB pathway to promote inflammation,reduce proinflammatory factor TNF-α and IL-6 release,in order to effectively inhibit the inflammatory cascade reaction,reduce the lung injury in rats.