Sirtuin 3 Inhibits Airway Epithelial Mitochondrial Oxidative Stress in Cigarette Smoke-Induced COPD

Figure 1

Decreased Sirt3 protein expression in airway epithelium of COPD rats is associated with airway epithelial mitochondrial damage. (a) Body weight of COPD rats was significantly decreased compared with the healthy control rats. (b) Arterial blood gas analysis results showed that PaO₂ significantly decreased and PaCO₂ was increased in COPD rats compared to control rats. (c) The numbers of total cells, neutrophils, and macrophages in BALF from the COPD group were significantly higher than those in the control group. (d) Representative HE staining of lung tissue sections (×200). (e) Representative electron microscope images of the ultrastructure alterations of airway epithelial cells in rats (×30000). COPD rats showed swollen mitochondria with fractured or dissolved cristae as indicated by the arrows. The scale bar represents 1 μm. (f) Representative immunohistochemistry image for Sirt3 in rat airway epithelium. The scale bar indicates 50 μm. (g) Quantification analysis of Sirt3 protein expression in lung tissue sections of COPD and control rats. The Sirt3 staining score is defined as the multiplication of staining intensity and percentage of stained cells, and the results showed that Sirt3 protein expression was significantly decreased in COPD rats compared to control rats. (h) The protein expression of Sirt3 in lung tissue homogenate was determined by Western blot. A representative blot is shown in the upper panel, and the quantification analysis shown in the lower panel displayed that Sirt3 expression was significantly decreased in COPD rats. Data are shown as ( and 8, respectively). compared to the control group.