The Expression Of CD31,CD54 In Bleomycin-induced Lung Fibrosis Of Rat

Objective: Idiopathic pulmonary fibrosis(IPF) is a distinct and specific form of pathology performance for usual interstitial pneumonia(UIP) in idiopathic interstitial pneumonia(IIP), is the most common kind in IIP. Its principal pathologic characteristics include alveolar epithelial cell, vascular endothelial cell and basal membrane damages, inflammation with neutrophils, macrophages, and lymphocytes, followed by proliferation of type II pneumocytes and fibroblasts, and collagen deposition. The accurate pathogenesis of IPF is still not clear, but in the earlier stage, the inflammation cell recruitment to the lung is mainly through cell adhesion molecule, so the adhesion molecule is paly a very important role in the process of formation of IPF. Both CD31and CD54 all belong to the immunoglobulin family of adhesion molecule. This article is for the purpose of investigating the expression of CD31, CD54 in Bleomycin-induced lung fibrosis of rat and how they play their roles in the pathogenesis of lung fibrosis.Material and method: 48 male Sprague Dawley(SD)rats in Cleaning Grade(provided by the Hebei Province experimental animal center), weight 230±10g, were randomly divided into two groups: the bleomycin (BLM) group and normal sodium group (treated with normal sodium, NS), each group is 24 rats. Each group by the compartment 3rd, 7, 14, 28th day randomly divides into four subgroups, each subgroup 6 SD rats. All operations are under the aseptic condition. After anaesthesia with 10% Chloral Hydrate (40mg/Kg) in the abdominal cavity injection, center incisal opening of the neck was made to fully expose the trachea. Puncture trachea gap of the cricoid cartilage, pour slowly physic liquor about 0.2ml~0.3ml(normal sodium contained BLMA5 5mg/Kg for the bleomycin group, the normal sodium for normal sodium group) into trachea, then keep the SD rats in erectly position and revolve gently, to distribute physic liquor fully in the lung. Rats were killed at 7day,14day, 28day and 40day. The left lung was made bronchoalveolar lavage (BALF) with the 2.5ml×3 normal sodium (recycle-ratio>80%). Centrifugate and count the cells. Fix the right lung in the 10% neutral formaldehyde solution, make the common paraffin section, then observe pulmonary alveolus inflammation by the HE dyeing and the collagen of lung tissue by the Masson dyeing. According to Maeyama method, classify sections in pathology, dyna- mic observe the development of pulmonary alveolus inflammation and lung fibrosis. Evaluate CD31 and CD54 expression in the lung tissue by using immunohistochemical method and make correlation analysis between CD31(CD54)expression and the total cell counts of broncho-alveolar lavage fluid. Statistics work was done with Spss11.5 statistical software.Results:1 Pathology of lung tissue. Normal sodium group: the lung tissues have pink smooth surfaces, with good elasticity in gross appearance. They had not been seen the obvious change under the microscope. Bleomycin group: the gross appearance of lung tissue: with the development of making the modle, gradually, color become pale, hemorrhagic spots and petechia appear, the surface become unsmooth, degree of hardness increase, elasticity decrease. Under the microscope, the degree of pulmonary alveolus inflammation and lung fibrosis are all obviously severe compared to that of the control group. Among the 3rd, 7, 14, 28th day subgroups, differences are obviously remark- able (p<0.05). Especially, the most severe pulmonary alveolus inflammation can be seen in the 7th day subgroups and the most severe lung fibrosis can be seen in the 28th day subgroups.2 Total cell counts and different analys in BALF from rats: The total number of cells (109/L) in bleomycin group were significantly higher than that in normal sodium control (P<0.001). The total number of cells in 7th day of bleomycin group were most (49.02±5.79), but later reduce. The total number of cells in 28th day of bleomycin group was still higher than that in 28th day of normal sodium control (P<0.001). In bleomycin group, the concentrations (%)of neutrophils and lymphocytes significantly increased than that in normal sodium group, in contrast, the concentrations(%) of macrophages decreased than that in sodium group (P<0.001).3 CD31 was positive in endothelial cell of bronchus-lung tissue of normal sodium group. In the 3rd day for bleomycin group, CD31 was obviously decreased, at the 7th day was lowest, and later increased, but was still lower compared with normal sodium group. The average gray scale of CD31 in bleomycin group at 3rd day, 7th day, 14th day and 28th day was much higher than the normal sodium group, and the difference at every point were significant (P<0.05). There were positive correlation between the average gray scale of CD31 and the total celluar score and also the score of neutrophil in bronchoalveolar lavage fluid CD31, the coefficient correlation were r=0.862, P=0.006; r=0.922, P=0.001.4 CD54 was weakly positive in endothelial cell of bronchus-lung tissue of normal sodium group, and CD54 was positive in bronchus- lung tissue of bleomycin group, it was expressed in alveolar epithelial cell, vascular endothelial cell, alveolar macrophage, bronchus epithelial cell. In the 7th day of bleomycin group, CD54 was at high peak, and later descent, but was still higher compared with normal sodium group. The average gray scale of CD54 in bleomycin group at 3rd day, 7th day, 14th day and 28th day was much lower than that the normal sodium group, and the difference at every point were significant(P<0.05). There were negative correlation between the average gray scale of CD54 and the total celluar score and also the score of neutrophil in bronchoalveolar lavage fluid, the coefficient correlation were r=-0.832, P=0.010; r=-0.863, P=0.006.Conclusions:1 Bleomycin-induced lung fibrosis in rat is successful,the model have good stability and predictability, higher in mission success rate, simple in operation, is one of better model in research lung fibrosis.2 The express of CD31 in the lung tissue of bleomycin-induced lung fibrosis in rat was decreased, that lead to the increase of vasopermeability, leukopedesis, endothelial cell injured and apoptosis. CD31 has participated the airsacculitis and the fibosis later.3 The express of CD54 in the lung tissue of bleomycin- induced lung fibrosis in rat was increase, that lead to gathering of the inflammation cells in the lung tissue. CD54 has participated the airsacculitis and the fibosis later.