Oxidative Stress in Rat Liver Tissues Induced by Endotoxin

[Objective] To explore the influences of endotoxin via intraperitoneal injection on several antioxidant enzymes in livers of rats.[Methods] The rats received injection of lipopolysaccharides(LPS) at different doses of 0.01,0.05,0.10,1.00 mg/kg.The activity of superoxide dismutase(SOD),Cu,Zn-SOD enzyme,catalase(CAT) and glutathione peroxidase(GSH-PX),and the content of GSH and malonaldehyde(MDA) in the supernatant of hepatic tissue homogenate were determined.[Results] Compared with the control group,there was no significant difference of SOD activity in the rats treated with 0.01,0.05 and 0.10 mg/kg LPS(P 0.05),but it decreased significantly at 1.00 mg/kg(P 0.01);the activity of Cu and Zn-SOD increased first and then decreased,and a significant difference was found in the 0.05 mg/kg group(P 0.01);the activity of CAT and the content of MAD decreased first and then increased,and they declined to the lowest point when treated with 0.05 mg/kg and 0.01 mg/kg respectively;the activity of GSH-PX and the content of GSH increased first and then decreased,and a significant difference was found in the 0.05 mg/kg group(P 0.01).[Conclusion] Low dose of LPS can induce adaptive responses in rat liver tissues,while high dose of LPS can lead to decrease of antioxidation in rat liver tissues,indicating that the toxic effects of LPS on rat livers may involve inducing excessive free radicals.