Abstract: AimTo investigate the antioxidant mechanisms of propylene glycol mannate sulfate (PGMS) in hyperlipidemic rats. MethodsMale Wistar rats were given high lipid emulsion diet to establish hyperlipidemic model. PGMS was given every day at different doses (37.8 and 75.6 mg·kg^-1, ig) to hyperlipidemic rats for three weeks. In addition, diethyldithiocarbamate (DDC) was given 200 mg·kg^-1·3d^-1 (ip) to inhibit SOD activity. Then, the MDA content was examined using TBA method to show the oxidation level, and the activities of SOD, GSH-Px and CAT were examined following the kit protocols to indicate the capability of eliminating OFR. RT-PCR was applied to study the expression of Cu, Zn-SOD mRNA in rat liver. ResultsThe MDA content of PGMS treatment groups decreased markedly compared with hyperlipidemic group, and the activities of SOD, GSH-Px and CAT increased distinctly. Cu, Zn-SOD mRNA expression was significantly increased by PGMS treatment. Furthermore, the application of DDC(the SOD inhibitor) reduced total SOD activity and Cu, Zn-SOD mRNA expression induced by PGMS, and the content of MDA increased correspondingly. ConclusionPGMS can induce the activities of antioxidant enzymes and the mRNA expression of Cu, Zn-SOD, which contribute to the elimination of oxygen free radical. This may explain the molecular mechanism of antioxidant effects of PGMS.