Background: An overwhelming production of reactive oxygen species concomitant with a decrease in antioxidative capacity plays an important role in modulation of the immune system in critically ill patients. The purpose of this study was to assess the influence of a combined oral supply of the antioxidants R-alpha-lipoic acid (LA) and glutamine (GLN) on the immunity of endotoxemic mice, with a special focus on tissue glutathione levels.
Methods: Female Balb/c mice were fed diets enriched with GLN (3 g/100 kcal), LA (0.74 mg/100 kcal), a combination of GLN and LA, or an isocaloric and isonitrogenous control diet for 10 days. On day 7, the mice were challenged intraperitoneally with 25 microg lipopolysaccharide. Seventy-two hours later, the number and phenotype of lymphocytes in Peyer's patches (PP) and spleen of the endotoxemic mice were measured. In addition, glutathione levels were determined in the small intestine, spleen and liver.
Results: In PP only the combined supply of GLN and LA significantly increased the total cell yield (+19%), which was predominantly due to an increased number of B cells. In the spleen, both LA (+17%) and the combination of GLN and LA (+22%) were able to enhance total cell yield. The glutathione content of the small intestine was increased by feeding LA alone, whereas in the spleen GLN plus LA was most effective.
Conclusion: Supplying combined GLN and LA to endotoxemic mice is effective in selectively increasing the number of systemic and intestinal B lymphocytes. Furthermore, LA augmented the level of the main intracellular antioxidant glutathione in the small intestine. On the basis of these data we recommend investigation of the effects of LA and GLN supplementation in patients with sepsis.