Abstract:

Objective To investigate the effects of A3 adenosine receptor (A3AR) agonist on lung injury after cardiopulmonary bypass (CPB) in rabbits. Methods Twenty-four rabbits were randomly divided into 3 groups, with 8 in each group. Rabbits in control group only received CPB, those in agonist group were given selective A3AR agonist IB-MECA intravenously 15 min before aorta clamp, and those in agonist+antagonist group were managed with selective A3AR receptor antagonist MRS-1191 intravenously before IB-MECA infusion. After CPB, serum concentrations of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8), concentrations of malondialdehyde (MDA) and myeloperoxidase (MPO) in lung tissues, lung wet/dry weight ratio (W/D), lung function related indexes of PaO₂/FiO₂, airway pressure (AWP) and pulmonary vascular resistance (PVR), and histological changes of lung tissues were observed.ResultsConcentrations of serum TNF-α and IL-8 were significantly lower in agonist group than in control group and agonist+antagonist group (P<0.05). Compared with control group and agonist+antagonist group, W/D was much smaller, and concentrations of MDA and MPO were significantly lower in agonist group after CPB （P<0.05). PaO₂/FiO₂ was significantly higher, while AWP and PVR were significantly lower in agonist group than in control group and agonist+antagonist group (P<0.05). It was revealed by histological examinations that the pathological changes were less severe in agonist group than in control group and agonist+antagonist group. Conclusion A3AR agonist IB-MECA can reduce lung injury after CPB.

Key words: A3 adenosine receptor agonist, cardiopulmonary bypass, lung injury