Effect of dietary selenium and injected gold thioglucose on adjuvant-treated rats

Gold (Au) thioglucose, which has been used in the treatment of rheumatoid arthritis, inhibits selenium (Se)-glutathione peroxidase. Since Au and Se play roles in inflammation, the effects of dietary Se (0, 0.2, and 2.0 ppm for 10 weeks) and injected gold thioglucose (5 mg Au/day/kg body weight for 28 days) in adjuvant-treated rats were investigated. Au toxicity was evidenced by lower body weights and higher tissue weight/body weight ratios for kidneys and spleens of Au-treated rats. Adjuvant-induced inflammation, measured by paw thickness, was not influenced by dietary Se, although Au decreased inflammation in Se-deficient rats. Liver glutathione peroxidase activity was depressed by Se deficiency and by Au. Sulfhydryl levels in liver soluble fraction and plasma were highest for Se-deficient rats. Among liver, kidney, spleen, and plasma, thiobarbituric acid reactants were highest in kidneys of Au-treated rats and lowest in plasma of rats fed 2 ppm Se. gamma-Glutamyltranspeptidase activity in plasma indicated liver damage in Se-deficient rats. Kidney PGE2 output in 24-hour urine samples was unaffected by Au, Se, or adjuvant. Au-Se interactions in vivo are complex, but decreased glutathione peroxidase activity in Au-injected rats suggests that Se nutrition of Au-treated rheumatoid arthritis patients may be a practical concern.