| Objective: Paraquat is a non-selective,inexpensive,efficient and eco-friendly herbicide.These characteristics have made it widely used in many countries around the world.However,paraquat is highly toxic to the human body,with particularly low lethality and no specific antidotes.Paraquat accumulates preferentially in the lungs due to accidental exposure,accidental ingestion or suicide,which can lead to inflammatory infiltration of lung tissue,pulmonary edema,destruction of alveolar structures within 3 days,causing acute lung injury.And in severe cases may develop acute respiratory distress syndrome,which is life-threatening.The main cause of acute lung injury is oxidative stress response that activates inflammatory cells,releases a large number of inflammatory factors,produces a cascade amplification effect,and eventually leads to a runaway inflammation and an imbalance of proinflammatory/anti-inflammatory cellular inflammatory factors.Therefore,in the treatment process of acute lung injury caused by paraquat poisoning,it is particularly important to control the inflammatory response early,reduce the release of pro-inflammatory mediators,increase the level of anti-inflammatory factors,and regulate pro-inflammatory/anti-inflammatory cytokine imbalances.Macrophages are widely present in the body and play an important role in regulating immunity,inflammatory response,maintaining homeostasis in the body,and resisting pathogen invasion.M0 macrophages,present in different tissues,can differentiate into M1 and M2 macrophages according to changes in the microenvironment of the organs in which they are located.M1 macrophages have pro-inflammatory response capabilities to produce pro-inflammatory cytokines,while M2 macrophages have anti-inflammatory abilities and the ability to repair damaged tissue.When a severe inflammatory response occurs in lung tissue after paraquat poisoning,if the polarization level of M1 macrophages and the polarization level of M2 macrophages can be reduced through the regulation of pathways,it can correct the imbalance of cytoinflammatory factors and alleviate acute lung injury,which provides new treatment ideas for the treatment of paraquat poisoning.However,the role of macrophage M1/M2 polarization in the process of acute lung injury caused by paraquat poisoning is currently poorly studied,and the relevant mechanisms are not clear.Firstly,paraquat was used to treat alveolar macrophages in mice to study the polarization of M1/M2 macrophages stimulated by paraquat.Subsequently,the effect of the m TORC1/p70S6 K pathway on the polarization of alveolar macrophages M1/M2,as well as the changes in inflammatory factors and acute lung injury,were observed in both vivo and vitro.Finally,the effect of PPAR-γ/STAT3 pathway on the polarization of alveolar macrophages M1/M2,as well as the changes in inflammatory factors and the degree of acute lung injury,were observed in both vivo and vitro,followed by paraquat infection stimulation,and the possible intrinsic biological mechanisms were analyzed.With macrophage functional differentiation as the core,the possible intrinsic biological mechanisms of macrophages are analyzed to explore new methods for the treatment of acute lung injury from paraquat poisoning.Methods: 1.Effect of acute poisoning of paraquat on the polarization of alveolar macrophage M1/M2.Paraquat infection was added to the culture medium of MH-S mouse alveolar macrophages,a cell model of paraquat poisoning was established,and the degree of polarization of macrophage M1 and IL-6 and TNF-α secretion levels were observed at three time points of 24 hours,36 hours and 48 hours,respectively,under the stimulation of paraquat at different concentrations of 0 μM,1 μM,5 μM,10 μM and25 μM.The polarization ratio of M1/M2 macrophages was observed at the time point with the highest inflammatory index.2.Effect of the m TORC1/p70S6 K pathway on the polarization of alveolar macrophage M1/M2 in acute lung injury caused by paraquat poisoning.The second part of the study was divided into two aspects: MH-S mouse alveolar macrophage vitro test and C57BL/6 mouse vivo test.In vitro,the m TOR inhibitor rapamycin was added to pretreatment before paraquat was infected,and changes in macrophage M1/M2 polarization as well as changes in the level of released cellular inflammatory factors were observed after infection 24 h,when m TORC1/p70S6 K pathway was inhibited.In vivo,a paraquat poisoning model was first established,m TORC1/P70s6 K pathway expression and the degree of acute lung injury in mice was observed at five time points of 6h,12 h,24h,48 h and 72 h.Then,before intraperitoneal injection of paraquat in mice,rapamycin was pre-injected intraperitoneally,and after 24 hours of poisoning,the polarization of macrophage M1/M2 in the alveolar lavage fluid of mice was observed,as well as the corresponding changes in the level of inflammatory factors and the degree of lung damage in alveolar lavage fluid.3.Effect of the PPAR-γ/STAT3 pathway on the polarization of alveolar macrophage M1/M2 in acute lung injury caused by paraquat poisoning and the potential therapeutic value of dexmedetomidine.The third part of the study is also divided into MH-S mice alveolar macrophage vitro test and C57BL/6 mouse vivo test.In vitro,the PPAR-γ agonist GW1929 and dexmedetomidine were added to the paraquat infection for pretreatment,and the poisoning was observed for 24 hours PPAR-γ/STAT3 pathway expression,changes in macrophage M1/M2 polarization,and changes in the level of released cytoinflammatory factors.In vivo before intraperitoneal injection of paraquat in mice,GW1929 and dexmedetomidine were injected intraperitoneally,respectively,and the expression of PPAR-γ/STAT3 pathway was observed after 24 hours of poisoning,and the macrophage M1/M2 polarization in the alveolar lavage fluid of mice was observed and corresponding changes in the level of inflammatory factors and the degree of lung damage in alveolar lavage fluid were also be observed.Subsequently,the inhibitor of PPAR-γ,GW9662,was used to intervene in the effect of dexmedetomidine,and whether the effect of dexmedetomidine on macrophage polarization and lung injury could be reversed after PPAR-γ inhibition.Results: 1.The level of M1 polarization of alveolar macrophages in mice is significantly elevated during acute poisoning of paraquat.After the alveolar macrophages of MH-S mice were infected,the polarization of M1 macrophages gradually increased at three time points of 24 hours,36 hours and 48 hours at the same paraquat concentration,and the secretion levels of IL-6 and TNF-α also increased simultaneously.Over the same time point,paraquat concentrations of 0 μM,1 μM,5 μM,10 μM,and 25 μM gradually increased with increasing concentrations of M1 polarization,and secretion levels of IL-6 and TNF-α were also increased simultaneously.Moreover,the polarization ratio of M1 macrophages after paraquat 25 μM action for 24 h was significantly higher than that of M2 type polarization.2.Inhibition of m TORC1/p70S6 K reduces alveolar macrophage M1 polarization levels in acute lung injury in mice caused by paraquat poisoning.In vitro,the m TOR inhibitor rapamycin was added to the pretreatment before paraquat infection,and the polarization level of macrophage M1 was significantly reduced after 24 hours of infection,and the concentration of IL-6 and TNF-α in the cell culture medium was also significantly reduced.In vivo,after intraperitoneal injection of paraquat 30 mg/kg,the degree of acute lung injury in mice was observed at five time points at 6 h,12 h,24 h,48 h,72 h,and the degree of lung injury was the most severe at 24 h,and the m TORC1/P70s6 K pathway was the most activated at 24 h.Before intraperitoneal injection of paraquat in mice,preintraperitoneal injection of rapamycin,after poisoning for 24 hours,the degree of M1 polarization of alveolar macrophages in mice decreased,the level of inflammatory factors in alveolar lavage fluid decreased,and the degree of lung damage was also reduced simultaneously.3.Activation of PPAR-γ inhibits the activation of STAT3,which can reduce the polarization of mouse vesicular macrophages M1 and increase the polarization degree of M2 after paraquat poisoning.Dexmedetomidine can also activate PPAR-γ,which has potential clinical value in treating paraquat.In vitro,the PPAR-γ agonist GW1929 and dexmedetomidine were added before paraquat infection,and PPAR-γ was activated after 24 hours of poisoning,and the STAT3 activity was inhibited,so that mouse alveolar macrophage M1 polarization was observed decreased,M2 polarization increased,and levels of cellular inflammatory factors in the culture medium decreased.In vivo,before the intraperitoneal injection of paraquat in mice,GW1929 and dexmedetomidine were injected intraperitoneally,respectively,and after poisoning for 24 hours,the lung tissue PPAR-γ of mice was activated,and the STAT3 activity was inhibited.Macrophage M1 polarization decreased and M2 polarization increased in alveolar lavage fluid,the level of inflammatory factors in alveolar lavage fluid decreased significantly,and the degree of lung damage decreased accordingly.Subsequently,the inhibitor of PPAR-γ,GW9662,intervened in the effect of dexmedetomidine,after PPAR-γ inhibition,STAT3 was activated,M1 polarization of alveolar macrophages in mice was increased and M2 polarization was decreased,the antiinflammatory effect of dexmedetomidine was reversed,and the mice suffered exacerbations of acute lung injury.Conclusion: 1.Mouse alveolar macrophages were significantly more polarized in M1 after paraquat poisoning,and the degree of this was positively correlated with the degree of exacerbation of lung inflammation.2.By inhibiting the m TORC1/p70S6 K pathway,the M1 polarization level of alveolar macrophages in mice after infection can be reduced,the secretion of pro-inflammatory factors can be reduced,and the degree of acute lung injury can be reduced.3.By activating PPAR-γ,the activation of STAT3 can be inhibited,thereby reducing the M1 polarization level of alveolar macrophages in mice after infection paraquat,increasing the level of M2 polarization,regulating the imbalance of inflammatory factors,and alleviating the degree of acute lung injury.4.Dexmedetomidine can also activate PPAR-γ,inhibit the activation of STAT3,reduce the level of M1 polarization of alveolar macrophages in mice after infection,increase the level of M2 polarization,regulate the imbalance of inflammatory factors,reduce the degree of acute lung injury,and have potential clinical value in the treatment of paraquat. |
PDF Full Text Request