| Objective:The chronic obstructive pulmonary disease combined with pulmonary interstitial fibrosis (PIF-COPD) is significantly different from idiopathic pulmonary fibrosis.The development of pulmonary interstitial fibrosis in COPD is an extremely common pathological changes.The fibrosis proliferation could be seen in peri-bronchial area,especially in the bronchial under grade VI.In severe cases, lesions could involve the respiratory bronchioles and alveolar walls.The main component of collagen in fibrosis area was identified as typeⅢ.PIF-COPD cause persistent airway stenosis and ventilation insufficiency deteriorated.The pulmonary interstitial and alveolar fibrosis are the results of lesions go into the lung tissue(surrounding bronchial under grade VI) along with the course of disease .It may be a repair response to inflammation and accounts for the dysfunction of pulmonary ventilation and gas exchange .Clinically it was discovered that COPD is often combined with a certain degree of pulmonary fibrosis,but the potential pathogenesis has not yet been clarified .In recent years,many Chinese and foreign study found that smoking and recurrent bacterial infection can accelerate the deterioration of COPD ,which provides an important basis for further exploration of this disease pathogenesis.Airway inflammation and remodeling are the main feature of COPD.The main reason of is the deposition of extracellular matrix mainly composed of collagen in the airway walls. Matrix metalloproteinase can degrade almost all the proteins in the alveolar walls ECM and the basement membrane,and participate in the respiratory reconstruction.This study aimed to observe the effect of the cigarette smoke and LPS on the chronic obstructive pulmonary disease with pulmonary interstitial fibrosis in rats,and discuss the pathogenesis mechanism of PIF-COPD,through detecting the levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in the lung tissue respectively as well as the level of typeⅢcollagen.The correlation between them was analyzed so as to provide the new idea about its prevention,diagnose and the therapy of anti-inflammatory combined with anti-fibrosis of PIF-COPD for clinic.Methods:twrenty-four male Sprague Dawley (SD) rats(provided by Center of Experiment Animal of Hebei Medical University), eight 250-300g, were randomly divided into three groups:normal control group (group A), 28-day model group (group B),42-day model group (group C).Group B and C were exposed in the box (40cm×50cm×60cm) by five cigarettes inhalation respectively one hour each time and two times in one day.In the 1st day and the 15th day,the group B was exposed in tratracheal by LPS (0.2ml/200ug). In the 1st day﹑15th and 28th day,the group C was exposed in tratracheal by LPS.All operations were under the aseptic condition.After anaeathesia with 10% Chloral Hydrate (40mg/Kg) in the abdominal cavity injection,center incisal opening of the neck was made to fully expose the trachea.The rats were punctured from trachea gap of cricoid cartilage,poured slowly LPS,then kept in erect position and revolved gently to distribute physic liquor fully in the lung.Eight rats in each group were sacrificed on 28 and 42 days respectively. The left lung was excised for HE,Masson Staining and detecting of lung coefficient.The level of typeⅢcollagen was measured by immunohisto- chemistry,and positive rate of typeⅢcollagendeterminedby sem quantitative picture analysis. MMP-9 and TIMP-1 measured by immunohistochemistry. Bronchoalveloar lavage fluid was obtained by bronchoalveloar lavage with 0.9% salin in BALF subgroup. BALF was collected and centrifugated (1200rpm, 4℃,10min).The sediment was infused with 0.9% salin to be counted the total leukocytes and PMN numbers.Results:1 In group B ,the total leukocytes and PMN numbers were higher than those of control group (P < 0.01).Comparing to control group,the percentage of macrophage decreased in group B and in group C. However,the lymphocyte numbers were higher than control group. 2 HE Staining on the lung tissueThe lung of group control rat had no change lesion in every point, but that of group B showed the features of pulmonary emphysema and acute inflammation: the alveolar wall were rupted and there were a few of macrophage and neutrophil in alveolar space ,with fibroblast increasing.The group C, alveolitis relieved, but hemorrhage and edema were still existing, with fibroblast increasing, interval widening obviously, collagen deposited and patches of fibrosis. alveolitis did not relieved obviously. Alveolar structure was destructed with fibroblast aggravated and alveolar space vanished.3 Masson Staining on the lung tissueThere was a little of collogen which color was blue in the microscope in group A. In group B and C, there were more collogen than that in group A, which collogen were obviously increased with time going on.4 typeⅢcollagen in lung tissue percentageThe result of immunohistochemistry suggested that the expression of typeⅢcollagen in lung tissue of group B and C were much higher than group A,and there were significant difference in groups (P<0.01).5 MMP-9 in lung tissueThe result of immunohistochemistry suggested that the expressions of MMP-9 in lung tissue of group B and C were much higher than group A,and there were significant difference in groups.6 TIMP-1 in lung tissueThe result of immunohistochemistry suggested that the expressions of TIMP-1 in lung tissue of group B and C were much higher than group A,and there were significant difference in groups.7 The pulmonary function in different groupIn model group B and C,percentage of forced expiratory volume in first 0.3 second to forced vital capacity (FEV0.3/FVC%), peak expiratory flow (PEF),maxium midexpiratory flow (MMF) were lower in comparison with control group (P<0.05),While inspiratory resistance (Ri) and expiratory resistance (Re) increased (P<0.05). In model group C, peak expiratory flow (PEF), maxium midexpiratory flow (MMF) were higher in comparison with B (P<0.05),While inspiratory resistance (Ri) and expiratory resistance (Re) decreased (P<0.05).Conclusions:1 The rats model of the chronic obstructive pulmonary disease combined with pulmonary interstitial fibrosis which were exposed in cigarette and LPS-induced were successful.2 Smoking and chronic recurrent airway inflammation may be involved in COPD with pulmonary interstitial fibrosis formation.3 The expression of MMP-9 and TIMP-1 of lung tissue gradually increase following the prolong of the time,it play an important role in COPD with pulmonary interstitial fibrosis .4 There is the same tendency between the degree of pulmonary and the current of the typeⅢcollagen of the tissue. |
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