Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia

Background Polymorphonuclear leucocytes (PMN) from subjects with primary ci liary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN fr om children with PCD. Design Membrane polarity was studied in 11 children with PCD and in healthy controls by measuring the steady-state fluorescence excitation and emissio n spectra of 2-dimethylamino[6-lauroyl]naphthalene (Laurdan), which is know n to be incorporated at the hydrophobic-hydrophilic interface of the bilaye r, displaying spectral sensitivity to the polarity of its surroundings. Lau rdan shows a marked steady-state emission red shift in polar solvents, with respect to nonpolar solvents. Moreover, the effect of the microtubule disa ssembling agent colchicine on PMN membrane polarity was evaluated. Result Our results show a red shift of the fluorescence excitation and emis sion spectra of Laurdan in PMN from the PCD group with respect to the contr ol group. These data indicate an increase in membrane polarity of PMN from the PCD group. Treatment of PMN with colchicine induced a red shift in the Laurdan excitation and emission spectra with the same trend observed in PMN from the PCD group. Conclusion PMN from children with PCD are characterized by an increased pla sma membrane polarity. These changes could be the basis of the modification s in the locomotory activities of PMN. The observed alterations may be attr ibuted to abnormalities in the cytoskeleton.