The Study Of Levosimendan On Experimental Caninelung Protection During Cardiopulmonary Bypass Surgery

Background: The development of CPB(cardiopulmonary bypass) technology is the milestone in heart surgeries, contributing to the development of open heart, while complications after CPB have a serious impact on the clinical outcome of patients, among which the postoperative ALI(acute lung injury) after CPB increases postoperative complications, prolongs the duration of hospital stays in ICU, and increases postoperative mortality. The mechanism of the postoperative ALI after CPB remains obscure, but may be related to various factors including CPB postoperative systemic inflammatory response(systemic inflammatory response syndrome, SIRS), ischemia-reperfusion injury(ischemia-reperfusion injury, I/R), apoptosis and the injuery caused by mechanical and physical factors. LS(Levosimendan), as a new generation of calcium sensitizer, lists firstly in 2000 in Sweden, which has significantly enhanced the function of myocardial contractility, and kept cellular oxygen consumption. The drug has been used clinically to treat a variety of diseases, such as acute heart failure. LS also has significant effects on the resistance to ischemic reperfusion injury, the proctection from apoptosis and the inhibition of the inflammatory cytokine production. In addition, some scholars have proven that LS also plays a role in protecting organs.Objective: To explore whether LS has a protective effect on the CPB postoperative ALI after CPB of experimental dogs.Methods: 32 dogs for experiment were randomly divided into four groups consisting of control group(group C), oxygen and cold-blooded pulmonary perfusion group(group P), LS intravenous group(group LSIV) and LS-containing oxygen and cold-blooded pulmonary perfusion group(group LSP), each with a LS dose of 65ug/kg. The malondialdehyde(MDA) content and the activity of superoxide dismutase(SOD) in the lung tissue were assayed for all the groups, and the pathological changes of lung tissue in each group were observed by light microscopy and electron microscopy.Results: Regarding the MDA content and the activity of SOD in the lung tissue, group LSP, group P and group LSIV have significantly decreased MDA content and greatly increased SOD activity(P<0.05) compared to group C, while group LSIV and group P have significantly increased MDA content and greatly decreased SOD activity(P<0.05) compared to group LSP, with no statistical significance for P group and LSIV group(P>0.05).Conclusion: By the simple pulmonary perfusion, pulmonary perfusion and intravenous injection of LS in canine animal models, it is demonstrated that the content of MDA decreases, the activity of SOD increases, and thus LS has a protective effect on lung tissue.