Effects of superoxide anion, B(alpha)P and TPA on the membrane fluidity of NIH3T3 cells

The membrane fluidity of NIH3T3 cells treated with low and high concentration of cell stimulatives (extracellular generated superoxide anion(O2-.),12-O-tetra-decanoyl-phorbol-13-acetate(TPA), and benzo(alpha)-pyrene[B(alpha)P]) was investigated by means of fluorescence labels 1,6-diphenyl-1,3,5 hexatriene (DPH) and N-(3-pyrene) maleimide (N(3p)M). The high concentration of O2-., TPA, B(alpha)P greatly increased the fluidity of cell membrane lipid domain. No changes of the florescence polarization of DPH was found in membrane lipid domain treated with low concentration of O2-., TPA, and B(alpha)P. However, decrease in the fluoresence polarization of N(3p)M on the cell membrane protein domain damaged by low concentration of cell stimulatives was observed, showing that these treatment could influence the conformation of membrane protein. The possible relationship between the changes of the conformation of membrane protein and the cell transformation and its carcinogenic machenisms were discussed.