Effects of lead on hepatic antioxidant status and transcription of superoxide dismutase gene in pigs.

Ninety-six castrated boars (Duroc x Landrace x Yorkshire) were randomly divided into four groups, each of which was replicated three times with eight pigs. The groups received the same basal diet supplemented with 0, 5, 10, and 20 mg/kg lead, respectively. The malondialdehyde and glutathione levels, antioxidant enzymes activities, and zinc/copper superoxide dismutase (Zn/Cu SOD) mRNA content in the liver were determined to evaluate the lead hepatic intoxication caused by the lead. Results showed the increased lipid peroxides level and the reduced glutathione content, along with a concomitant decrease in the activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, the level of hepatic Zn/Cu SOD mRNA was also significantly reduced. We suggest potential mechanism for lead intoxication in liver as follows: lead causes parallel decrease in Zn/Cu SOD mRNA and activities of antioxidant enzymes, leading to the declined ability of scavenging free radicals with excessive production of lipid peroxides, which seriously damages the hepatic structure and function.