Role of the anionic component in manifestation of effects of organic lithium salts on oxidativemodification of blood proteins and lipids in patients with depressive disorders

Abstract

Introduction. Lithium salts are widely used in psychiatry. Studying new properties of lithium salts with various anionic components is important. The aim of this study was to compare in vitro effects of lithium salts containing different organic anionic components on oxidative modification of plasma proteins and lipids in patients with depressive disorders (DD). Methods. Blood ofDD patients was incubated with lithium salts (lithium ascorbate, lithium succinate, and lithium pyruvate) at 37°C for 1 hour. Ethanol was used as an oxidizing agent. Final concentrations of lithium ions and ethanol in a sample were 1.2 mM and 0.5%, respectively. Plasma content of oxidized proteins was determined by the content of carbonylated proteins (CP) using 2,4-dinitrophenylhydrazine. Lipid peroxidation products were determined by the content of thiobarbituric acid-reactive products (TBA-RP). Results. In DD patients, concentration of CP was increased compared to the control (healthy subjects) whereas concentration of TBA-RPdid not differ from the control. Incubation of blood from healthy individuals with 0.5% ethanol resulted in increases in both theCP and TBA-RP whereas ethanol did not exert any effect on concentrations of oxidized proteins and TBA-RP in DD patients in thesame conditions. Lithium ascorbate and lithium pyruvate in the presence of ethanol increased the CP concentration in blood fromDD patients; lithium succinate left unchanged the CP concentration in these conditions. None of the studied compounds had anyeffect on TBA-RP in plasma of DD patients. In blood of healthy donors, lithium salts exerted an antioxidant effect increasing theresistance of plasma macromolecules to the toxic (oxidative) action of ethanol. Conclusion. The studied lithium salts producedan antioxidant effect in vitro on ethanol-induced oxidative modification of proteins and lipids in blood from healthy individuals. Inblood samples from DD patients, lithium salts containing ascorbate or pyruvate anions showed pro-oxidant properties by potentiating the oxidative effect of ethanol on plasma proteins but not lipids. Therefore, lithium salts differently influence in vitro oxidative modification of proteins and lipids in blood of healthy people and DD patients with the anionic component of lithium saltplaying an important role in manifestation of effects of these compounds.