Expression Of P53 In Lung Tissue Of Rats With Chronic Obstructive Pulmonary Disease And Its Relationship With Apoptosis Of Alveolar Epithelial Cells

Objective: To investigate the expression of p53 protein and alveolar epithelial cells apoptosis in lung tissue of rats by establishing a chronic obstructive pulmonary disease(COPD)rat model by injecting lipopolysaccharide into the trachea and to explore the relationship between the expression of p53 and the apoptosis of COPD in lung tissue under the intervention of p53 inhibitor(PFT-?).Methods: 48 SD rats were randomly divided into normal group(group A),COPD model group(group B),COPD+p53 inhibitor solvent dimethyl sulfoxide group(group C)and COPD+p53 inhibitor group(group D).Each group has 12 rats.Any treatment won't be done to Group A,while B,C,D group were treated with cigarette smoking and intratracheal instillation of lipopolysaccharide to create COPD rat model.At the same time,rats' abdominal cavity in group D will have the injection of p53 inhibitors,rats in group C recieve injection of the same amount of p53 inhibitor solvent,and group B is not treated separately.The rats were sacrificed 28 days later.HE staining in lung tissues were used to observed the pathological changes.Thecontent of p53 protein was determined by immunohistochemistry(Western blotting).The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay(TUNEL)was used to detect the apoptosis of lung tissue and the apoptosis index was calculated.Results:1.The pathology of the lung tissueTracheal mucosal epithelium in rats' lung tissue in normal group is integrited.A group little inflammatory cell around the airway were infiltrated and alveolar size and structure is normal situation.B group,the infiltration of inflammatory cells was observed in the lung tissue.The trachea and bronchial mucosa were observed to be lobed,necrotic,and the alveolar wall became thinner or ruptured.The alveolar cavity was enlarged and even merged,suggesting that rat lungs meet emphysema changes.More inflammatory cell infiltration are shown in the lung tissue of the D group,but the number of bronchial and bronchial mucosa was decreased with thephenomenon of cilia necrosis,destruction of alveolar structure and enlargement of alveolar cavity,but the degree was less than that of the model group.The infiltration of inflammatory cells in the lung tissue of the rats in the C group was not significantly different from that in the B group.2.TUNEL detecting alveolar epithelial cells apoptosis of lung tissueIn B group(33.94±3.20%),C group(32.84±3.39%)and D group(25.08±2.29%),compared with the A group(11.53±2.84%),the apoptoticrate of alveolar epithelial cells increased(P<0.05).Compared with the B group,and the C group,the alveolar epithelial cells of the D group decreased(P<0.05).There was no significant difference in alveolar epithelial cells between the B group and the C group(P>0.05).3.Immunohistochemistry detecting p53 protein expression in lung tissueP53 protein was mainly expressed in alveolar epithelial cells and vascular endothelial cells.Compared with the A group(12.78±1.57%),p53 protein expression in the B group(67.29±2.83%),the C group(66.05±3.18%)and the D group(41.77±2.92%)was significantly increased(P<0.05);Compared with the B group and C group,p53 expression in the D group was decreased(P<0.05).There was no significant difference in p53 expression between B group and C group(P>0.05).4.The correlation analysis of apoptosis index and p53 protein expression in ratsThe expression of p53 protein in the lung tissue correlated positively with apoptosis index of alveolar epithelial cells in each group(P<0.05).Conclusion: 1.The apoptosis of alveolar epithelial cells and the expression of p53 protein increased in COPD rats.2.The expression of p53 protein in lung tissue was positively correlated with the apoptosis of alveolar epithelial cells in COPD rats.3.P53 inhibitors can reduce the apoptosis of alveolar epithelial cells in COPD rats.