Inhibition of lipid peroxidation, protein glycation and elevation of membrane ion pump activity by taurine in RBC exposed to high glucose.

BACKGROUND: Supplementation of taurine, a sulfur containing amino acid has been found to be beneficial in counteracting oxidative stress and in preventing experimental diabetic neuropathy, nephropathy and retinopathy. Taurine has its own capacity to prevent the suppression of membrane-bound Na(+)/K(+)ATPase activity and prevent Ca(2+) overload. This study was undertaken to test whether taurine can reduce lipid peroxidation and glycosylation and can increase the Na(+)/K(+)- and Ca(2+)-ATPase activities in high glucose-treated red blood cells (RBC).
METHODS: Washed normal human RBC were incubated in phosphate-buffered saline with normal (6 mmol/l) or high glucose concentrations (45 mmol/l), with and without 50-150 micromol/l taurine in a shaking water bath at 37 degrees C for 24 h. Lipid peroxidation, glycated hemoglobin, glucose utilization and Na(+)/K(+)- and Ca(2+)-ATPase activities were determined in the glucose-treated human RBC.
RESULTS: Taurine significantly lowered the level of glycated hemoglobin (GHb) and lipid peroxidation in RBC exposed to high glucose concentrations. Stimulation of glucose utilization by RBC was significant in the presence of taurine both in normal and high glucose-treated RBC. The activities of Na(+)/K(+)- and Ca(2+)-ATPases in RBC membranes were significantly lowered in high glucose-treated RBC. Taurine treatment significantly prevented the reduction in activities of Na(+)/K(+)- and Ca(2+)-ATPases activities in high glucose-treated RBC.
CONCLUSIONS: The results show that taurine is important for the physiological functions of RBCs and the effects of taurine on glucose-treated RBC may have potential therapeutic relevance in diabetes.