Effect of sevoflurane post-conditioning on apoptosis and the expressions of Bcl-2 and Bax in lung tissue of cardiopulmonary bypass dogs

Abstract

Purpose: To investigate the effects of sevoflurane post-conditioning on the expressions of Bcl-2 and Bax in lung tissues of cardiopulmonary bypass (CPB) dogs. Methods: Twelve healthy hybrid mongrels were divided into control (C) and sevoflurane postconditioning (S) groups. All dogs were subjected to thoracotomy in order to establish CPB. Ischemiareperfusion was conducted in the left lung of both groups. Thereafter, sevoflurane post-conditioning was given to group S. Femoral artery blood specimens were obtained prior to CPB (T1), as the left pulmonary artery was opened (T2), and 2 h after CPB (T3), for blood gas analysis. Respiration index (RI), oxygenation index (OI), and dynamic lung compliance (Cd) were calculated. Results: When T1 was compared with T2 and T3, their OI and Cd were significantly decreased in both groups, while RI showed the opposite trend (p < 0.05). Values of OI and Cd at T3 in group S were increased significantly, relative to group C, while RI decreased (p < 0.05). There were less lung tissue inflammation and structural disorder at T3 in Group S than in group C. Protein expressions and positive integral of Bcl-2 and Bax, and apoptosis at T2 and T3 in dog lung tissues of both groups were higher than those at T1 (p < 0.05). Conclusion: Post-conditioning with sevoflurane is lung-protective in CPB dogs. The underlying mechanism may be based on the promotion of Bcl-2 expression and inhibition of Bax expression, thereby reducing apoptosis in dog lung tissue. Further investigations to determine its suitability for clinical applications in humans are, however, required. Keywords: Sevoflurane; Cardiopulmonary bypass; Bcl-2, Bax; Apoptosis; Pulmonary ischemiareperfusion injury