ABSTRACT: Sera from Duchenne muscular dystrophy (DMD) patients showed a membrane fluidizing effect on DMD and control lymphocytes. To look for the cause of this membrane fluidizing effect, human lymphocytes from healthy subjects were incubated in sera and in different serum fractions from DMD patients and healthy control subjects, and membrane fluidity was determined by steady state fluorescence polarization of the probe diphenyl hexatriene. DMD sera and total DMD lipoproteins showed a similar membrane fluidizing effect (p<0.02) after incubation, whereas lipoprotein deficient serum did not show any effect on membrane fluidity. Control and DMD HDL showed a membrane fluidizing effect, the fluidizing effect of DMD HDL being slightly higher as compared to control HDL. Control LDL and DMD LDL showed a membrane rigidifying effect, the rigidifying effect of DMD LDL being significantly lower as compared to control LDL (p<0.02). These data demonstrate that the membrane fluidizing effect of DMD serum is lipoprotein associated, LDL being the most important mediator of this effect.
Dr Fabio Facchinetti, Clinica Ostetrica e Ginecologica, Universit´ degli Studi, Via del Pozzo 71, 41100 Modena, Italy.