Apoptosis Of Type â…¡ Alveolar Epithelial Cells In Chronic Obstructive Pulmonary Disease (COPD) Rats And The Effects Of Inhaled Glucocorticoid

Objectives:To investigate the apoptosis of type Ⅱ alveolar epithelial cells in pulmonary tissue of the rats model of chronic obstructive pulmonary disease (COPD) and observe the effects of inhaled glucocorticoid on its expression in order to explore the role of apoptosis of type Ⅱ alveolar epithelial cells in the pathogenesis of COPD. Methods:A rat model of COPD was established by tobacco smoke inhalation and intratracheally given LPS (200μg/μl). Forty-eight twelve-weeks-old male SD rats were randomly divided into control group, BUD group, COPD fifteen days group, inhaled low dose glucocorticoid(BUD) fifteen days group, inhaled high dose glucocorticoid (BUD) fifteen days group , COPD thirty days group, inhaled low dose glucocorticoid (BUD) thirty days group and inhaled high dose glucocorticoid (BUD) thirty days group. The degrees ofalveolar destruction was observed by hematoxylin- eosin stained pathological sections and apoptosis of type Ⅱ alveolar epithelial cells in pulmonary tissue was measured by immunohistochemistry and TUNEL methods.The results were processed semiquantitatively by image analysis. Results:1. The degrees of alveolar destruction of COPD rats were increased significantly than those in BUD and control group(P<0.01),and the increase was time-independent(P<0.01);The apoptosis of type Ⅱ alveolar epithelial cells in COPD rats were increased significantly than those in BUD and control group(P<0.01),and the increase was time-independent (P<0.01);and they also exhibited a significantly positive correlation with each other.2. Inhaled glucocorticoid could significantly decrease the degrees of alveolar destruction of COPD rats(P<0.01) and the decrease was dose-independent (P<0.01). Inhaled glucocorticoid could partly decrease the apoptosis of type II alveolar epithelial cells in COPD rats but the effect was no significant defference (p>0.05) . Conclusion:1.Tabocco smoke inhalation and intratracheally given LPS could establish COPD model in SD rats successfully.2. The expression level of type Ⅱ alveolar epithelial cells apoptosis in COPD rats were increased significantly than those in BUD and control group, which also exhibited a positive correlation with the degrees of alveolar destruction. The apoptosis of type Ⅱ alveolar epithelial cells may be involved in the formation of COPD by alveolar destruction,but the mechanism was still unknown.3. Inhaled glucocorticoid could significantly decrease the degrees of alveolar destruction of COPD rats and the decrease was dose-independent.Inhaled glucocorticoid could partly decrease the apoptosis of type Ⅱ alveolar epithelial cells in COPD rats but the effect was no significant defference.The results also supply a experimental evidence for Inhaled glucocorticoid used for COPD treatment.