Changes Of PigR And IgA In Lung Tissue Of Chronic Obstructive Pulmonary Disease

Objective:To observe the differential expression level of sIgA,pIgR,dIgA in the lung tissues of COPD patients and rats which exposed to silica dust,and the pairwise correlation between sIgA,pIgR,dIgA,mean airway thickness of bronchioles(VV _airway)and FEV₁%pred was analyzed.To explore the different expression level of sIgA,pIgR and dIgA in COPD patients and rats exposed to silica dust with different severity.Methods:1.Consecutive 30 cases of pulmonary lesion patients,hospitalized with Pulmonary lobectomy,were included.The study was conducted from January 2015 to December 2018in thoracic surgery of Shanxi Dayi Hospital.The study included 4 females and 26 males with an average age of 61±8 years.One week before operation,all patients completed lung function,the function of liver and renal,the function of blood coagulation,blood cell composition analysis and so on.Meanwhile,recorded all indexes,such as FEV₁%pred and FEV₁/FVC.According to the results of pulmonary function examination and postoperative pathological diagnosis,the patients with FEV₁/FVC（29）0.7 and benign lesions were included in the healthy control group,and the patients with FEV₁/FVC<0.7 and non-small cell cancer were included in the COPD group.And then,according to the level of FEV₁%pred,the COPD group was divided into mild to moderate COPD group（FEV₁%pred≥50%）and severe COPD group（30%≤FEV₁%pred<50%）.Each group contains 10 subjects.The site of the specimen was more than 5 cm away from the diseased tissue.HE sections and wax fragments of lung tissues with bronchioles were extracted from the tissue specimen bank in pathology department of Shanxi Dayi Hospital.Exclusion criteria:（1）Accompanied by otherlung diseases,such as bronchial asthma,bronchiectasis,interstitial lung disease and so on.（2）Accompanied by severe heart,liver,kidney,Endocrine and immune system related diseases.（3）patients with obstructive pneumonia owing to various causes.（4）COPD patients in acute exacerbation.（5）patients with preoperative radiotherapy or chemotherapy.（6）patients who were unable to cooperate and completely unable to communicate.Our research has been approved by the Ethics Committee of Shanxi Dayi Hospital.All subjects voluntarily signed informed consent after being informed of the content and purpose of the study.2.Thirty-two adult healthy male Wistar rats were randomly divided into 15 days normal feeding group,15 days silica dust exposure group,30 days normal feeding group and 30days silica dust exposure group.The rats of normal feeding group received saline and the rats of silica dust exposure group received silica.All rats were fed with ordinary diet and fed with free food and drinking water.The lung tissues of rats were sampled at 15 days and 30days after administration with silica dust,respectively.Then fixed,dehydrated,paraffin embedded,and stored at room temperature for reserve.All Experiments and surgical procedures were approved by the Laboratory Animal Care and Use Committee at Capital Medical University,which abides by the National Institute of Health Guide for the Care and Use of Laboratory Animals.3.Paraffin sections of lung tissue from all patients and rats were sliced,and common HE stained slides and cationic anti-shedding immunohistochemical slides were prepared.4.The pathological change of lung sections stained with HE was observed under microscope.The images of bronchioles in 5 visual fields were collected and the mean airway wall thickness of terminal bronchioles(VV _airway)was calculated at the same time.5.The immunohistochemical staining was completed by automatic immunohisto-chemical instrument.The images were collected and imported into Image-Pro^○RR Plus software for quantitative analysis of sIgA,pIgR and dIgA protein.Then calculated and recorded the average optical density of sIgA,pIgR and dIgA protein.6.And then completed the statistical analysis.Results:1.Changes of lung tissue in patients under microscopeUnder HE staining microscope,the pulmonary tissue of patients with COPD showed thickening of bronchiolar wall,degeneration and necrosis of epithelial cells,cilium lodging and loss,thinning and rupture of alveolar septum,enlargement of alveolar cavity and formation of pulmonary bullae.In contrast with mild to moderate COPD patients,the above pathological changes in lung tissue of severe COPD patients were more severe.Under the immunohistochemical staining microscope,brown yellow particles were observed in the cilium and cytoplasm of the lung epithelial cells in control group and mild to moderate COPD group,and a little brown yellow particle was found below the basal layer of the epithelial cells.2.The level changes of of sIgA,pIgR,dIgA,VV _airway and FEV₁%pred in lung tissue of patients in each groupIn contrast with control group and mild to moderate COPD group,the level of sIgA,pIgR protein in lung tissue of severe COPD group was lower.while in contrast with control group and mild to moderate COPD group,the level of dIgA protein was significantly higher（All P<0 05）.In contrast with control group and mild to moderate COPD group,the VV _airway in the severe COPD group was higher.And in contrast with control group,the VV _airway in the mild to moderate COPD group was also higher（All P<0 05）.In contrast with control group and mild to moderate COPD group,the FEV₁%pred in severe COPD group was lower.And in contrast with control group,the FEV₁%pred in mild to moderate COPD group was also lower（All P<0 05）.3.Correlation analysis of the levels of sIgA,pIgR,dIgA,VV _airway and FEV₁%pred in lung tissue of patients in each groupIn control group and mild to moderate COPD group,there had no pairwise correlation between the levels of sIgA,pIgR,dIgA,VV _airway and FEV₁%pred.In severe COPD group,the positive and pairwise correlation was found between sIgA,pIgR and FEV1%pred.The level of sIgA was negatively correlated with dIgA and VV _airway,respectively.And the level of pIgR was also negatively correlated with dIgA and VV _airway,respectively.However,dIgA was positively correlated with VV _airway,and dIgA and VV _airwayirway were negatively correlated with FEV₁%pred.4.Changes of lung tissue in rats under microscopeUnder HE staining microscope,we observed thickening of bronchiolar wall,degeneration and necrosis of epithelial cells,cilium lodging and loss in the lung tissue of rats exposed to silica dust.And the longer the exposure time was,the more serious the pathological changes were.Under the immunohistochemical staining microscope,there were obvious brown yellow particles in the ciliated layer and cytoplasm of the lung epithelial cells in the normal feeding group and 15 days silica dust exposure group,but no brown yellow particle was found below the basal layer of the epithelial cells.In the 30 days silica dust exposure group,no brown yellow particle was found in the ciliated layer and cytoplasm of the lung epithelial cells,but the brown yellow particles were evident below the basal layer of the epithelial cells in the rats exposed to silica dust for 30 days.5.The level changes of sIgA,pIgR,dIgA and VV _airway in lung tissue of rats in each groupThe level of sIgA,pIgR protein in the 30 days silica dust exposure group was lower than that in the 15 days normal feeding group,15 days silica dust exposure group and 30days normal feeding group.while in contrast with other three groups,the level of dIgA in the 30 days silica dust exposure group was significantly higher（All P<0.001）.The VV _airway in the silica dust exposure group was higher than that in the normal feeding group,and the VV _airway in the 30 days normal feeding group was significantly higher than that in the 15 days silica dust exposure group（All P<0.001）.6.Correlation analysis of the levels of sIgA,pIgR,dIgA and VV _airway in lung tissue of rats in each groupThere was no pairwise correlation between the level of sIgA,pIgR,dIgA and VV _airwayirway in the 15 days normal feeding group,15 days silica dust exposure group and 30 days normal feeding group.In the 30 days silica dust exposure group,sIgA and pIgR had notable positive correlation,sIgA was negatively correlated with dIgA and VV _airway,pIgR was negatively correlated with dIgA and VV _airway,and dIgA was positively correlated with VV _airway.Conclusions:1.Down regulation of sIgA and pIgR and aggregation of dIgA in lung tissue of COPD patients are associated with disease severity and bronchial epithelial remodeling,suggesting that IgA-related airway mucosal immune barrier is impaired in severe COPD patients.2.Down regulation of sIgA,pIgR and aggregation of dIgA in the lung tissue of rats exposed to silica dust are related to the silica dust exposure time and bronchial epithelial remodeling,suggesting that long-term exposure to toxic particles may lead to IgA-related airway mucosal immune barrier dysfunction.