Determination Of The Concentration Of SIgA In BALF In Rats With Chronic Obstructive Pulmonary Disease And Diabetes Mellitus

Objective To determine the concentration and differences of SIgA in bronchoalveolar lavage fluid (BALF)and observe the changes of pathological structure in lung tissue in the rats model of chronic obstructive pulmonary disease (COPD).diabetes mellitus (DM) and chronic obstructive pulmonary disease plus diabetes mellitus (COPD+DM)Methods 48 rats were divided into four groups:normal group, COPD group, DM group, and COPD+DM group. There were 12 rats in each group. Bred in the experiments environment for one week, the DM model was established. Absolute diet 12h,then the rats were intraperitoneally injected with streptozotocin solution at the dose of 60 mg/kg. After 72 hours, the blood was collected from rat vena caudalis,the blood glucose was determined by glucose meter,the blood glocuse that was higer than 16.7mm/l was considered as the model success.one week later, The COPD model was established by cigarette inhalation and intratracheal LPS exposure. After the DM model was estabalished, we used the same method of the COPD group to model the COPD+DM group. After the rats model success, all rats were anaesthetized by intraperioneally injected with 10% chloral hydrate at the dose of 4 ml/kg. Cut ribcage apart,take out the right lung tissues to observe the changes of pathological structure.The left lung was lavaged to determine the concentration of SIgA in BALF by the method of ELISA.Results①Pathological changes of lung tissue:In normal group, the size of alveolus was normal and structural was integrity, cilia arranged neatly, no inflammatory cells infiltration was found..In COPD group,the bronchial epithelium were ablated, and the interstitial pulmonary and airway walls were infiltrated with inflammatory cells,The rupture and enlarged alveolus and bullaes were identified alveolar wall became thin and fracture.In DM group,there were inflammatory cells infiltration under the basement membrane, the lodging cilias of bronchial epithelium and the increased capillary. Enlargement of alveolar septum, incereased collagen and elastin of extracellular matrix were also found.In COPD+DM group, the bronchial epithelium were ablated severely, and the interstitial pulmonary and airway walls were infiltrated with abundant inflammatory cells.The structure of alveolus were destroyed and some of them formed into bullaes.②Concentration of SIgA in BALF:Compared with the normal group, the concentration of SIgA in COPD group decreased (P<0.01),but increased in the DM group and COPD+DM group (P<0.01);Compared with the COPD group,the concentration of SIgA in the DM group and COPD+DM group increased significantly (P<0.01);There was no difference in the concentration of SIgA between DM group and COPD+DM group (P>0.05).Conclusion (1) The pathological damage changes of the lung tissue were all observed in COPD group and DM group.(2) The concentration of SIgA in COPD group decreased significantly as compared with the normal group, which indicated that the pulmonary mucosal immunity declined in COPD group.(3) The concentration of SIgA in the DM group and COPD+DM group increased, which could be related to the immune response of advanced glycosylation end products (AGEs) and the increased compensatory immune to pathogenic microorganisms., we suppose the structure or function of this SigA is abnormal, which can not sustain the normal defensive function.