Abstract: AIM: To investigate the effects of compound salvia miltiorrhiza (SM) injection on lung injury after cardiopulmonary bypass (CPB).METHODS: Twenty-four rats were randomly divided into control group, CPB groupand SM group.Cardiopulmonary bypass was made in rats of CPB groupand SM group.Lung tissues of all rats were taken 60 min after the weaning of CPB for the assay of malondialdehyde (MDA) , myeloperoxidase(MPO) , water content of tissue, the observation of pathological changes were made under optical microscope.RESULTS: Remarkable pathohistological and biochemical changes were detected 1 h after CPB.Compared with control group, MDA in lung tissue were increased in CPB groupand SM group(p<0.05) , but MDA in SM groupwas lower than that in CPB group(P<0.05).Similarly, the level of MPO and water content were increased markedly compared with control groupand SM group(p<0.05).Accordingly , swelling and infiltration of leucocyte were found in lung tissue of CPB groupunder an optical microscope.These pathohistological damages caused by CPB were greatly attenuated in SM group.CONCLUSION: CPB-related lung injury can be reduced by compound salvia miltiorrhiza injection which has free radical scavenging and neutrophil infiltration relieving activities.

Key words: cardiopulmonary bypass, lung injury, compound salvia miltiorrhiza injection, rats