Mild laboratory-induced metabolic disorder in rats. Effect on erythrocyte membrane according to a dielectroscopic study

Abstract

This study concentrates on the effect of mild metabolic disorder (MMD) in fructose-fed rats on the submembrane skeleton MS of their erythrocytes relying on the relationship between membrane structure and its dielectric properties. The segmental flexibility of MS and its attachment to the lipid membrane of erythrocytes is expressed by the MS intrinsic dielectric polarization. The latter was assessed by the difference in dielectric properties of erythrocytes (complex impedance, Z*, and capacitance, C*) prior to and after the thermal denaturation of spectrin assuming the dielectric activity of denatured spectrin nil. The erythrocytes of control (n=4) and fructose-fed (n=5) rats were isolated, washed, suspended in isotonic 10 mM NaCl/mannit solution (hematocrit 0.45) and heated (1.5 °C/min). At the denaturation temperature of spectrin (49°C) the dielectric properties of erythrocyte suspension sustained threshold changes ΔZ*=ΔZre + jΔZim and ΔC*=ΔCre - jΔCim. The frequency analysis of ΔZre, ΔZim, ΔCre and ΔCim indicated strongly increased contribution of spectrin to the dielectric properties of erythrocyte membrane. Thus, spectrin contribution to the static capacitance of erythrocyte membrane was 83 % greater and that to the dipole loss of erythrocyte membrane was 38 % greater in erythrocytes from MMD rats, compared to control RBCs. This finding is suggested to be due to the moderate increase in glucose level and related increase in phosphorylation of membrane proteins in MMD rats.