MECHANISM OF HEMOLYSIS OF HUMAN ERYTHROCYTES EXPOSED TO MONOSODIUM URATE MONOHYDRATE CRYSTALS - PRELIMINARY CHARACTERIZATION OF MEMBRANE PORES

Microcrystals of monosodium urate monohydrate (MSUM) have the ability to cause rapid hemolysis of erythrocytes. The nature of the initial MS UM crystal-erythrocyte membrane binding interaction was investigated o ver a range of different ionic strength media. There was negligible bi nding of MSUM to erythrocyte ghost membranes in low ionic strength med ia such as isotonic mannitol but binding was dramatically increased in isotonic NaCl/mannitol solutions or isotonic mannitol containing 1 mM Ca2+. Hemolysis induced by MSUM crystals was preceded by the leakage of K+ from the cells suggesting a colloid-osmotic mechanism of hemolys is. The inclusion of large (oligosaccharide) molecules in the extracel lular media or the modulation of the extracellular solution tonicity i nhibited both the rate and extent of hemolysis supporting the concept of MSUM-induced pores followed by colloid osmotic hemolysis.