Resistivity of red blood cells against high-intensity, short-duration electric field pulses induced by chelating agents

The interaction of human red blood cells (RBCs) with diethylenetriamine-pen taacetic acid (DTPA) or its Gd-complex (Magnevist, a widely used clinical m agnetic resonance contrast agent containing free DTPA ligands) led to the f ollowing, obviously interrelated phenomena. (i) Both compounds protected er ythrocytes against electrohemolysis in isotonic solutions caused by a high- intensity DC electric field pulse. (ii) The inhibition of electrohemolysis was observed only when cells were electropulsed in low-conductivity solutio ns. (iii) The uptake of Gd-DTPA by electropulsed RBCs was relatively low. ( iv) (Gd-) DTPA reduced markedly deformability of erythrocytes, as revealed by the electrodeformation experiments using high-frequency electric fields. Taken together, the results indicate that (Gd-) DTPA produce stiffer eryth rocytes that are more resistant to electric field exposure. The observed ef fects of the chelating agents on the mechanical properties and the electrop ermeabilization of RBCs must have an origin in molecular changes of the bil ayer or membrane-coupled cytoskeleton, which, in turn, appear to result fro m an alteration of the ionic equilibrium (e.g., Ca2+ sequestration) in the Vicinity of the cell membrane.