Abstract

Comparison of Effective α-Tocopherol Concentrations Ameliorating Reduced Glucose Transport and Counteracting t-Butyl hydroxyperoxide- Induced Lipid Peroxidation in Isolated Erythrocytes from β-Thalassemic Patients

Chris Adhyanto, Marice Sihombing, Hans-Joachim Freisleben, Rondang R. Soegianto, Septelia I. Wanandi and Ridwan Rahmawati

In thalassemia patients Red Blood Cell (RBC) membrane is the major target of oxidative stress caused by hemichrome radicals. Moreover, RBC membranes from thalassemic patients are more susceptible to oxidative stress, which causes lipid peroxidation, membrane rigidity, and dysfunction of membrane proteins. We investigated hemoglobin-free isolated RBC membranes (ghosts) from 28 β-thalassemia major patients and from 24 normal blood samples. Our research aimed to determine the effective concentrations of racemic α-tocopherol i) counteracting experimental oxidative stress induced by 2mM tertiary butylhydroperoxide (t-BHP) and ii) ameliorating impaired glucose transport in RBC ghosts from thalassemia patients. Reduced glucose transport in thalassemic ghosts was ameliorated significantly by tocopherol with a maximum effect at 75 ppm concentration. Furthermore, ghosts were pre-incubated with/without α-tocopherol up to 200 ppm before treated with t-BHP as the oxidative agent and reactive membrane thiols determined. As a parameter of lipid peroxidation (LPO) thiobarbiturate-reactive substances were measured and expressed as malondialdehyde levels. Tocopherol counteracted LPO continuously in a concentration-dependent way up 200 ppm. Hence, it is concluded that tocopherol acts at different concentrations as an antioxidant and on glucose transport by GLUT1 in RBC membranes.