The Relationship Between The Pathological Changes Of Alveolar Septum And Lung Function In Patients With Chronic Obstructive Pulmonary Disease

Objective: To investigate the pathological changes of alveolar septum in patients with chronic obstructive pulmonary disease(COPD)and its relationship with airflow limitationMethods: A single-center prospective study,analysis postoperative pathologic specimens of patients with lung tumors.Cases were divided into COPD and normal control group according to lung function.The pathological specimens were selected should be at least 2cm from the lesion and in the subpleural lung tissue.Hematoxylin-eosin staining was used to be observed the morphology of lung tissue and the thickness of alveolar septum.Elastica Van Gieson staining was used to be observed the ratio of elastic fibers and collagen fibers in alveolar septum.The levels of matrix metalloproteinase-2 ? matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 were detected by immunohistochemical staining.FEV1%pred indicates the severity of COPD airflow limited.To compare the histopathological changes of alveolar septum between two groups and almong the different severity of COPD groups.To observe the relationship between the pathological changes of alveolar septum and FEV1% pred,DLco% pred and the relationship between MMP-2,MMP-9 and TIMP-1.Results:1 A total of 60 patients were enrolled in the study,there were 40 patients in the COPD group and 20 patients in the control group.There was no significant difference in sex,age,smoking index and specimen acquisition site between the two groups.The DLco%pred in the severe COPD group was lower than that in other groups.2 It showed that the elastic and collagen fibers arranged disorder in alveolar septum and alveolar septal fracture significantly increased,alveolar cavity expansion obviously in the COPD group.3 The thickness of alveolar septum was 6.90 ±2.11 um and collagen fibers were accounted for 47.6 ± 12.62% of alveolar septum in COPD group,it was higher than the control group.The elastic fibers accounted for 37.43 ± 12.96%,the elastic fiber /collagen fiber was 82.87 ± 38.85%,they were lower than the control group(P<0.05).In the COPD groups,the thickness of the alveolar septum was 9.00 ± 4.78 um and collagen fibers accounted for 59.5 ± 13.52% in the severe COPD group they were higher than the mild and moderate COPD groups.The elastic fibers accounted for27.88% and elastic fibers / collagen fibers were 48.38 ± 17.97% in severe COPD group it was lower than the mild and moderate COPD groups(P <0.05).4 The relationship between the alveolar septum pathological changes and pulmonary function:1)FEV1%pred was negatively correlated with alveolar septum thickness and the proportion of collagen fiber(r =-0.335,-0.472;p = 0.035,0.002),and positive correlation with the proportion of elastic fibers and elastic fibers/collagen fibers(R =0.316,0.522;P = 0.047,0.001);2)DLco%pred was negatively correlated with the proportion of Collagen fibers(r-0.329 P = 0.010),and positively correlated with the proportion of elastic fibers and elastic fibers/ collagen fibers(R = 0.316,0.452,P =0.014,0.000).5 The expression level of MMP-2,MMP-9 and TIMP-1 in the COPD group were higher than that in the control group(P <0.05);The expression level of MMP-2,MMP-9,TIMP-1 in the Severe COPD group were higher,while the ratio of MMP-2/TIMP-1,MMP-9/TIMP-1 were lower than those in mild and moderate COPD groups(P <0.05).Conclusion:In COPD patients alveolar septal fibers arranged disorder,alveolar septal fracture increased;alveolar septum thickness was more thicker.The proportion of collagen fibers increased and that of elastic fibers decreased.FEV1%pred were negative correlated with the thickness and the proportion of collagen fibers,while the proportion of elastic fibers were positive correlated with FEV1%pred;DLco%pred was negative correlated with proportion of collagen fibers and was positive correlated with the proportion of Elastic fibers.The expression level of MMP-2,MMP-9 and TIMP-1 in alveolar septum of COPD patients increased,the ratio of MMP-2/TIMP-1,MMP-9/TIMP-1 were lower than mild or moderate COPD groups.Alveolar septal pathological changes were related to lung function and MMPs.