| Objective:Severe acute pancreatitis(SAP)is sudden inflammation of the pancreas that can be complicated by involvement of other distant organs.Studies have shown that the incidence rate of severe acute pancreatitis has increased year by year in recent years,among which acute lung injury(ALI)is the most common type of organ failure in the early stage of severe acute pancreatitis.Currently,there is no curative treatment for SAPALI clinically.The main functions of the lung-air-blood barrier include exchanging oxygen and carbon dioxide with the atmosphere and defending against the invasion of external pathogens.Once destroyed,it often leads to inflammation and oxidative stress in the lungs.Previous studies mainly focused on symptomatic and supportive treatment,lacking specific therapeutic drugs.Bone Marrow Mesenchymal Stem Cells(BMSCs)have shown a good ability to repair damaged tissues,but their transplantation rate and survival rate in vivo are currently the main difficulties.Here we mainly explore the protective effect of Qingyi Decoction(QYD)on improving the damaged lung microenvironment and improving the lung-qi-blood barrier of bone marrow mesenchymal stem cells in a rat model of acute pancreatitis with lung injury.Methods:Healthy male Sprague Dawley(SD)rats were randomly divided into five groups:sham operation group(SHAM),model group(SAP),Qingyi decoction group(QYD),bone marrow mesenchymal stem cell group(BMSCs)and clear Pancreatic decoction combined with bone marrow mesenchymal stem cells(QYD-BMSCs),10 rats in each group.3.5% sodium taurocholate(3.5% STC)was used to establish the SAPALI model.After modeling,the QYD group was intragastrically administered three times a day,and the other groups were intragastrically administered with the same dose of normal saline;the BMSCs group was injected with 500 μl PBS through the tail vein 4 hours after modeling(BMSCs transplantation dose is 1 × 106/kg),the same dose of PBS in the other groups was injected into the tail vein;the QYD-BMSCs group was gavaged three times a day and injected into the tail vein 4 hours after modeling.All groups were collected 48 hours after modeling.The fluorescence intensity of Di R-labeled BMSCs in lung tissue was observed by near-infrared small animal fluorescence imaging system;histopathological observation and scoring of pancreas and lung tissue by HE staining;serum inflammatory factor IL-6 and lipase content,alveolar Levels of inflammatory factors IL-6 and TNF-α in lavage fluid;BCA method to detect total protein content in alveolar lavage fluid;immunohistochemical method to detect changes in levels of MPO and 4-HNE in lung tissue;immunofluorescence to detect AQP5 in lung tissue,SPC,Occludin and ZO-1 expression;Western Blot to detect alveolar epithelial cell proliferation and Evans blue penetration test to measure pulmonary microvascular endothelial permeability.Results:We used isoflurane to anesthetize the rats,pulled the pancreas out of the abdomen after laparotomy,clamped the biliopancreatic duct proximal to the liver with vascular clips,and then slowly retrogradely injected 3.5% STC into the biliopancreatic duct to establish severe acute Rat models of pancreatitis-related lung injury were collected at 48 hours.We found that QYD increased the fluorescence signal of Di R-labeled BMSCs in lung tissue at 1,3,6,and 24 hours,and the fluorescence signal of BMSCs was the strongest at 3 hours.In addition,compared with the SHAM group,the pathological damage of the lung tissue and pancreas of the rats in the SAP group was the most obvious.;serum lipase content of rats in SAP group showed an upward trend;The tissue wet/dry weight ratio was significantly increased;the content of pro-inflammatory factor IL-6 in the serum of the SAP group increased;the inflammatory factors IL-6,TNF-α and the total protein content was significantly increased,and the expression of alveolar epithelial cells in the SAP group was increased;the permeability of the pulmonary microvascular endothelium was significantly increased in the SAP group.Compared with the SAP group,the pathological scores of lung tissue and pancreas,the content of serum lipase and pro-inflammatory factor IL-6,the wet/dry weight of lung tissue of rats after administration of QYD or BMSCs Ratio and other disease indicators were improved to varying degrees.In addition,the content of pro-inflammatory factors IL-6,TNF-α and total protein in alveolar lavage fluid,the expression of alveolar epithelial cells and pulmonary microvascular endothelial permeability were also significantly reduced.Interestingly,we found that compared with the BMSCs alone group,QYD-BMSCs had a better therapeutic effect on reducing lung inflammation and oxidative stress levels and repairing the lung air-blood barrier.Conclusion:In this experiment,the SAPALI model in rats was established by retrograde injection of 3.5% STC into the biliopancreatic duct,and the rats were sacrificed 48 hours after the model was established.During SAP,the systemic inflammatory response was severe in rats,with significant pancreatic damage and infiltration of inflammatory factors in the lung tissue accompanied by edema.BMSCs treatment can reduce the level of lung inflammation and oxidative stress to a certain extent,and protect the damaged lung air-blood barrier.The addition of QYD can improve the ability of BMSCs to protect the damaged lung air-blood barrier.QYD improves the ability of BMSCs to protect the lung air-blood barrier in severe acute pancreatitis,possibly by improving the lung microenvironment.This may be a new strategy for the clinical treatment of lung injury in severe acute pancreatitis. |
