Selenium prevents lithium accumulation and does not disturb basic microelement homeostasis in liver and kidney of rats exposed to lithium.

INTRODUCTION: Lithium has been used in medicine for almost seventy years. Besides beneficial effects, its therapy may cause serious side-effects, with kidney and liver being the organs most vulnerable to its harmful influence. Therefore, research on protective agents against lithium toxicity has been continuing for some time. OBJECTIVE: The aim of the present study is to evaluate the influence of additional selenium supplementation on lithium content, as well as homeostasis of the essential microelements iron, zinc, copper and manganese in kidney and liver of rats undergoing lithium exposure. MATERIAL AND METHODS: The study was performed on 4 groups of male Wistar rats (6 animals each) treated with: control - saline; Li-group - Li2CO3 at a dose of 2.7 mg Li/kg b.w.; Se-group - Na2SeO3 at a dose of 0.5 mg Se/kg b.w.; Li+Se-group - both Li2CO3 and Na2SeO3 at doses of 2.7 mg Li/kg b.w. and of 0.5 mg Se/kg b.w., respectively, in the form of water solutions by stomach tube, once a day for 3 weeks. The content of the studied elements in the organ samples was determined using flame atomic absorption spectroscopy (FAAS). RESULTS: Lithium administered alone caused a significant increase in its content in liver and kidney. Additional supplementation with selenium reversed these effects, and did not markedly affect other studied microelements compared to control. CONCLUSIONS: The obtained results suggest that selenium could be regarded as an adjuvant into lithium therapy. However, considering the limitations of the present study (the short duration, using only one dose and form of selenium) the continuation of the research seems to be necessary to clarify the influence of selenium supplementation on basic microelements and lithium accumulation in organs during lithium exposure.

Targeting Antioxidants to Interfaces: Control of the Oxidative Stability of Lipid-Based Emulsions.

The oxidation of lipid-based emulsions and nanoemulsions strongly affects their overall quality and safety. Moreover, introduction of oxidatively unstable emulsions into biological systems either as an energy source in parenteral nutrition or as delivery systems of bioactives may promote oxidation "in situ" leading to the overproduction of reactive oxygen species, initiating new harmful oxidative reactions and increasing the oxidative damage. Addition of antioxidants, AOs, may help to prevent the oxidative degradation of unsaturated lipids. Nevertheless, prediction of the optimal antioxidant or set of antioxidants and their efficiency is still far from being completely understood because the site of reaction is often uncertain and because the effective concentrations of reactants in the different regions of the emulsion have been frequently overlooked. Furthermore, the absence of quantitative relationships between the hydrophobicity of the antioxidants and their partitioning among the oil, water, and interfacial regions hampers their optimal use. Here we investigated the effects of gallic acid and some of its alkyl derivatives on the oxidative stability of soybean oil-in-water emulsions and determined their effective concentrations in the different regions of the emulsion (aqueous, oil, and interface). The results provide physical evidence for the crucial role played by the interfacial region in the reaction between antioxidants and lipid radicals: a direct relationship between interfacial concentrations and the oxidative stability could be established. The results indicate that AOs accumulate in the interfacial region, where the effective concentration is 20-180 times higher than the stoichiometric concentrations. Control of the hydrophobicity of the AOs and of the surfactant concentration allows control of interfacial concentrations: the lower the concentration of surfactant employed, the higher the effective interfacial concentration.