Abstract: Objective To investigate the protective effects of rhein lysinate (RHL) on cardiac tissue damage induced by paraquat in experimental mice, and to clarify its mechanism. Methods In this study mice were assigned to the following three groups: control, paraquat model, and RHL-treated groups. The model of oxidative damage mice was established by intraperitoneal injection of paraquat. RHL-treated group was given RHL (50 mg/kg) by gavage for one week before performing model. The other two groups were given equal volume of distilled water. For making model, paraquat was intraperitoneally injected in the paraquat model and RHL-treated group. The content of MDA was detected by thiobarbituric acid assay. The activities of SOD and GSH-Px were detected by biphenyl three phenolic autoxidation assay and NADPH coupling method respectivly. The pathological profile of cardiac tissue was observed by hematoxylin and eosin (HE) staining and reactive oxygen species was observed by DCFH-DA staining. The change of proteins related to myocardial damage detected by Western blot. Results Compared with control group, the activities of SOD and GSH-Px were decreased (p<0.05) and the content of MDA was increased (p<0.05) in paraquat model group. However, these changes were attenuated after RHL treatmen (p<0.05). The pathological examination indicated the structure of cardiac tissue was damaged and reactive oxygen species of cardiac tissue was increased after paraquat was given, however, these changes were attenuated after RHL treatmen. It was shown in western blot analysis that compared with control group, the expression of SIRT1 was decreased, the acetylation of p53 and the expression of p53 and p66 were increased in paraquat-treated group. These changes were attenuated after RHL treatmen (P<0.05). Conclusion RHL could attenuate paraquat-induced cardiac injury in mice

Key words: Rhein lysinate, paraquat, cardiac injury, reactive oxygen species