DPH标记细胞膜的动力学与膜脂流动性的荧光偏振校正测量

用稳态荧光技术测得经过校正的荧光成分,由此算出用DPH标记的细胞膜的偏振度。方法是作荧光偏振值在随时间变化的曲线,将其外推至零标记时间求出该时间的荧光偏振值。用此法测定了艾氏腹水癌细胞的膜流动性。结果表明流动性比用整个细胞测得之值小,说明膜脂的有序程度和包装密度比胞浆中的脂大。实验结果和用三房空模型分析所得的理论值符合较好,提示荧光探剂的标记过程主要受分子扩散所控制。

DYNAMICS OF LABELLING CELL MEMBRANE WITH DPH AND THE CORRECTED DETERMINATION OF MEMBRANE FLUIDITY BY FLUORESCENCE POLARIZATION

The fluorescence polarization degree of fluorescence probe DPH labelled in cells was calculated from corrected fluorescence components measured by steady-state fluorescence technique.The plot of fluorescence polarization vs. labelling time was made and the fluorescence polarization of DPH located in cell membrane was obtained by extrapolating this curve to zero labelling time. In this way, the membrane fluidity of living Ehrlich ascite tumor cells was determined.Results show that the fluidity of cell membrane is less than that from whole cell determination,indicating that the order and the packing density of lipids are higher in cell membrane than in plasma.The experimental data fit well with that from three-compartment model analysis, it suggests that the fluorescence probe labelling process is mainly controlled by molecular diffusion.