| Objective The main purpose of this study was to study the expression and clinical characteristics of SIRTs in lung tissues of patients with chronic obstructive pulmonary disease(COPD),and to explore the relationship between alveolar epithelial cell senescence and mitochondrial autophagy in COPD patients,so as to further reveal the role and mechanism of mitochondrial autophagy and pulmonary epithelial cell senescence in COPD.Methods A total of 30 normal lung tissues of normal non-smoking patients,normal smoking patients and COPD patients admitted to people’s Hospital from January 2019 to December 2020 were collected and divided into three groups:normal control group,normal smoking group and COPD group.The general clinical data of patients in each group were analyzed and compared: age,sex,body mass index,smoking index,lung function(FVC,FEV1/FVC,FEV1,% predicted value).The lung tissue of each group was examined by routine pathology and transmission electron microscope.The expression levels of SIRT1,SIRT3,PINK1,Parkin and FOXO3 A mRNA in lung tissue were detected by qRT-PCR.The expression levels of SIRT1,SIRT3,PINK1,Parkin,FOXO3 A and p21,p53,LC3 A,LC3B protein in lung tissue were analyzed by immunohistochemistry,and the senescence-related β-galactosidase(SA β-gal)activity in lung tissue of patients in each group was detected.The correlation between SIRT1,SIRT3 and PINK1,Parkin protein expression was analyzed by Pearson straight line method.Results There was no significant difference in FVC between the normal group,the normal smoking group and the COPD group(P>0.05);the FEV1/FVC and FEV1% predicted values of the COPD group were significantly lower than those of the normal group and the normal smoking group(P<0.05);.Routine pathology showed that compared with the normal group,the lung tissue cavity of the COPD group was significantly enlarged and the number of alveoli decreased,which was consistent with the pathological changes of emphysema.The quantitative analysis of lung tissue morphology showed that the average lining interval and average alveolar area of the COPD group were significantly higher than those of the normal group and the normal smoking group,while the average number of alveoli per unit area was significantly lower than that of the normal group and the normal smoking group(P<0.05).Compared with the normal control and normal smoking group,the activity level of SA-β-gal in the COPD group was significantly increased(P<0.05);qRT-PCR results showed that compared with the normal group and normal smoking group,the COPD group had lung tissue SIRT1,SIRT3,The expression level of FOXO3 A and Parkin mRNA was significantly reduced,while the expression level of PINK1 mRNA was significantly increased(P<0.05).Western blot results showed that the lung tissue SIRT1,SIRT3,FOXO3 A,and Parkin protein expressions of patients in the COPD group were relatively normal and normal smoking Significantly reduced,and p53,p21 and PINK1,LC3 A,LC3B protein expression levels were significantly increased(P<0.05).Perarson analysis showed that the expression level of SIRT1 and PINK1 protein in the lung tissues of COPD patients was significantly negatively correlated(R=-0.658,P<0.05),while it was significantly positively correlated with the expression level of Parkin(R=0.532,P<0.05)There was a significant negative correlation between SIRT3 and PINK1 protein expression level(R=-0.697,P<0.05),and a significant positive correlation with Parkin protein expression level(R=0.516,P<0.05).Conclusion Cell senescence is up-regulated and autophagy levels in lung tissues of patients with COPD are up-regulated or down-regulated to varying degrees.There is a linear relationship between the cell senescence and autophagy,SIRT1 may be involved in the AECII aging process through SIRT1/SIRT3/FOXO3 A and PINKl/Parkin signaling network-regulated mitochondrial autophagy mechanism. |
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