Objective  To investigate the intervention effect of 3-phosphoinositede dependent protein kinase-1 (PDK1) inhibitor on prostaglandin E2 (PGE2) in smoking-induced chronic obstructive pulmonary disease (COPD) mice. Methods  Fifty C57BL/6 male mice were randomly divided into normal control group, smoking group, smoking +low dose PDK1 inhibitor group, smoking + medium dose PDK1 inhibitor group and high dose PDK1 inhibitor group with 10 mice in each group. The mice in the normal control group inhaled phosphate-buffered saline twice a day for 12 weeks, and the mice in the smoking group were fumigated twice a day, 5 days per week for 12 weeks, and the other three groups were given intraperitoneal injection of low-dose PDK1 inhibitor OSU-03012 (0.25 mg/kg), medium-dose PDK1 inhibitor (0.5 mg/kg) and high-dose PDK1 inhibitor (1.0 mg/kg) respectively before smoking. After smoking, lung function was tested, the bronchoalveolar lavage fluid (BALF) of each mouse was taken for cell count, the PGE2 in serum and BALF of mice was determined by enzyme linked immunosorbent assay, and the lung tissue of mice was sectioned with paraffin and stained by hematoxylin-eosin (HE), and pathological changes were observed under microscope. Results  Compared with the control group, FEV₁₀₀/FVC and FEV₂₀₀/FVC of the mice in each smoking group were significantly decreased (P<0.05); The number of cells in BALF of smoking group was significantly higher than that of normal control group (P<0.05). There was no significant difference in the total number of BALF cells, the proportion of neutrophils and macrophages between the smoking + low-dose PDK1 inhibitor group and the smoking group. However, the total number of BALF cells and the proportion of neutrophils in the smoking + medium dose PDK1 inhibitor group and the high dose PDK1 inhibitor group gradually decreased, while the proportion of macrophages gradually increased, compared with the normal control group, the PGE2 concentrations of serum and BALF in the smoking group and the smoking + PDK1 inhibitor group were significantly higher than those in the control group. Compared with the smoking group, the PGE2 concentrations of serum and BALF in the middle and high dose PDK1 inhibitor groups were significantly lower than those in the smoking group. HE staining of lung tissue showed that there were a large number of inflammatory cell infiltration, alveolar cavity dilatation, alveolar wall rupture and fusion, alveolar formation, significant decrease in the number of alveoli and other pathological changes in the smoking group, which were consistent with the pathological changes of COPD. The inflammatory cell infiltration, mucus obstruction and alveolar dilatation were slightly alleviated in the smoking + low-dose PDK1 inhibitor group, while the inflammatory cell infiltration, alveolar wall thinning and alveolar dilatation were improved in both the medium-dose inhibitor group and the high-dose inhibitor group, and the improvement was more obvious in the high-dose inhibitor group. Conclusion  The lung function of the smoked COPD mouse decreases, the airway inflammation is obvious, and the secretion of PGE2 is also increased, while the use of PDK1 inhibitor could reduce the secretion of PGE2, reduce airway inflammation and pathological changes, and improve lung function in a dose-dependent manner.

Citation： WU Yonghong, WANG Ke, LIU Chuntao. Intervention effect of PDK1 inhibitor on PGE2 expression in smoking-induced COPD mouse model. Chinese Journal of Respiratory and Critical Care Medicine, 2023, 22(5): 349-355. doi: 10.7507/1671-6205.202208038 Copy