Evaluation Of Gastric Lavage Elimination Effects Of Paraquat Poisoning And TLR3/NF-kappa B Signaling Pathway In Paraquat-induced Acute Lung Injury

Background:Acute poisoning is one of the most common diseases in emergency department.The third national cause of death survey showed that poisoning and injury were the fifth major causes of death after malignant tumor,cerebrovascular disease,respiratory disease and heart disease,accounting for 10.7% of the total mortality rate.Paraquat(PQ)is the most widely used herbicide in the world.The mortality rate of poisoning is the first in China,which has become a serious public social problem and emergency medical problem.Due to the lack of antidote and effective treatment,it is believed that gastric lavage(GL)is one of the most critical early therapies for early and effective elimination of toxic substances,and which is also the key link in the treatment of PQ poisoning.However,details of the protocol for this treatment remain to be established.Additionally,In clinical,PQ is mostly ingested by digestive tract,but the most serious damage organ is lung.The mechanism of irreversible damage to lung tissue caused by PQ poisoning has not been fully known.In this study,the mechanism of GL in a swine paraquat poisoning model and paraquat-induced acute lung injury in a mouse paraquat poisoning model was studied.Through the experimental results,(1)a reasonable GL time point and appropriate elution volume were provided,and(2)the effect of TLR3 and NF-kappa B on acute lung injury induced by PQ poisoning also were provided,to provide the theoretical basis and research direction for PQ poisoning.Part oneObservation and evaluation of gastric lavage effects in a paraquat poisoning swine modelObjective:The gastric juice and eluent were detected by a rapid quantitative method,which to observe and evaluate the GL effects in a paraquat poisoning swine model.Methods:18 female pigs were administered a 60-mg/kg dose of PQ solution intragastrically and were randomly divided into a PQ group,a GL with 20 L of water at H1 group and a GL at H6 group(n=6 in each group).The PQ concentrations in the gastric juice were detected at H1 and H6 before GL and at H24.During GL,each 10 L eluate sample was collected and homogenized to calculate the washing efficiency.Results:The reaction conditions of the test were optimized for two types of samples.At H24,the vital signs of the swine,the blood routine and biochemical parameters in the PQ group were significantly deteriorated in comparison to those observed at H0.comparison with the PQ group,most of the indicators have improved at H24 in GL groups(P <0.05),and the PQ concentrations in the gastric juice were significantly decreased after GL in both groups.There were no significant differences in the washing efficiencies calculated from the first(17.79±4.56% vs.12.42±4.91%)or second(3.99±2.22% vs.3.35±1.97%)10 L eluates between the two GL groups.However,the PQ concentrations in the first 10 L eluates were significantly higher than those in the second 10 L eluates in both GL groups.Conclusion:Our study suggests that GL can reduce the toxicity of PQ to the body,and the washing efficiency of the first 10 L eluate is superior to that of the additional 10 L eluate.Part twoTLR3/NF-kappa B signaling pathway in paraquat-induced acute lung injuryObjective:To investigate the pathogenesis of PQ induced acute lung injury through Toll like receptor 3(TLR3),TLR induced nuclear transcription factors(NF-?B)and its downstream inflammatory factors tumor necrosis factor-alpha(TNF-?),interleukin-1 beta(IL-1?)and interleukin-6(IL-6).Methods:The acute lung injury model of mice and the acute injury model of type II alveolar epithelial cells(A549)induced by PQ were established.The PQ mediated pathological changes of lung tissue,the cell count and cytospin of bronchoalveolar lavage fluid(BALF)were evaluated,and the inflammatory factors were subjectd to ELISA assay in the lung tissue of mice;the viability of A549 cells mediated by PQ was detected by CCK8 assay,and the m RNA or protein expression of TLR3,Phospho-NF-k Bp65,TNF-?,IL-1?,IL-6 in the lung tissues and A549 cells were observed by Real-time PCR and Western-blotting.Results:Compared with the control group,the mice in PQ group showed difficulty breathing,decreased activity,reduced food intake,and weight lost.The total number of BALF cells in the PQ group was significantly increased,lymphocyte and neutrophils.In PQ group,the appearance and volume of lung tissue increased with hyperemia and edema(all P < 0.05)..HE slices showed inflammatory cell infiltration and pulmonary interstitial hemorrhage.Moreover,the expression of TNF-?,IL-1?,IL-6 in BALF of PQ group was significantly higher than that of the control group by the ELISA assay.CCK8 results indicated that the viability of A549 cells decreased by 25.3% and 36.4% at H24 after 200-400 ?mol/L PQ treatment(all P < 0.05).The m RNA expression of TNF-?,IL-1?,IL-6 in the lung tissue and A549 cells in PQ group was higher than that in the control group as well(all P < 0.05).Furthermore,Western-blotting results revealed that the protein level of TLR3 and Phospho-NF-?Bp65 in the lung and A549 cells mediated by PQ was significantly higher than that in the control group(all P < 0.05).Conclusions:PQ may induce acute lung injury by up-regulation of the expression of inflammatory factors TNF-?,IL-1?,IL-6 through the TLR3/NF-?B signaling pathway,therefore,our work provides novel ideas and targets for the intervention of acute lung injury caused by PQ poisoning.