Exogenous opioid peptide preconditioning in prevention of pulmonary ischemia-reperfusion injury in pigs after cardiopulmonary bypass / 第二军医大学学报

ABSTRACT

Objective: To evaluate the protective effect of δ-opioid peptide, [D-Ala2-D Leu5]-enkephaline (DADLE), on pulmonary ischemia-reperfusion (I-R) injury after cardiopulmonary bypass (CPB), and to discuss the possible mechanism. Methods: Twenty-eight male pigs were evenly randomized divided into 4 groups, namely, the sham operation group, the CPB group (only subjected to CPB), the DADLE pretreatment group (received DADLE 1 mg · kg-1 before CPB), and the Glibenclamide group (received DADLE 1 mg · kg-1 and glibenclamide 1 mg · kg-1 before CPB). Peak inspiratory pressure (PIP), PaO2, and the plasma malondialdehyde (MDA) concentration were measured in each group before CPB and 10 min, 30 min, and 60 min after reperfusion. The changes of lung tissue wet weight/dry weight ratio (W/ D) were calculated before CPB and 60 min after reperfusion. The animals were sacrificed 60 min after reperfusion to observe the ultrastructural changes of the lungs and to quantitatively assess lung tissue damage (LTD). Results: There were no significant differences among the 4 groups before CPB and the parameters in sham-operation group had no changes at all specified time points. One hour after reperfusion, the PIP, MDA, W/D, and LTD values in Glibenclamide and CPB groups were significantly higher than those in sham-operation and DADLE groups while the PaO2 was significantly lower(P<0.05 or 0.01). There were no significant differences between parameters of sham-operation and DADLE groups except for LTD(P<0.05). There were no significant differences between parameters of Glibenclamide and CPB groups. Histological examination demonstrated that the degree of lung injuries in sham-operation and DADLE groups were slighter than those in Glibenclamide and CPB groups. Conclusion: It suggests that DADLE may exert its protective effect on the lung through opening ATP-sensitive K+ channels, so as to alleviate the lung I-R injury after CPB.