Monosodium urate monohydrate crystal induced changes in membrane fluidity: a fluorescence polarization study.

The hydrophobic fluorophore 1,6-diphenyl-1,3,5-hexatriene was incorporated into erythrocyte ghosts. After incubation of the labelled ghost membranes with monosodium urate monohydrate (MSUM) crystals, low speed centrifugation was used to separate ghosts bound to MSUM from "free" ghosts. The fluorescence anisotropy of ghosts with bound crystals was significantly lower than for free ghosts, indicative of an increased membrane fluidity. Possible mechanisms for the fluidization of ghosts membranes after MSUM binding and the relationship of this to cellular membranolysis are discussed.