Change of membrane fluidity of rat neutrophils accompanying Escherichia coli inoculation

• Published in: Journal of leukocyte biology Vol. 46; no. 2; p. 169
• Main Authors: Masuda, M, Komiyama, Y, Nishikado, H, Kuriki, H, Egawa, H, Murata, K
• Format: Journal Article
• Language: English
• Published: United States 01-08-1989
• Subjects: Actin Cytoskeleton - drug effects; Animals; Cell Membrane - drug effects; Cell Membrane - physiology; Cell Membrane - ultrastructure; Colchicine - pharmacology; Cytochalasin B - pharmacology; Edetic Acid - pharmacology; Escherichia coli; Injections, Intravenous; Male; Membrane Fluidity - drug effects; Microtubules - drug effects; Neutrophils - microbiology; Neutrophils - physiology; Neutrophils - ultrastructure; Rats; Rats, Inbred Strains
• ISSN: 0741-5400
• DOI: 10.1002/jlb.46.2.169

Membrane fluidity of rat neutrophils was studied following Escherichia coli inoculation, and characteristic changes were observed. Membrane fluidity was assessed by the excimer-forming lipid technique using pyrenedecanoic acid and flow cytometry and expressed as the fluorescence intensity ratios of excimer and monomer pyrenedecanoic acid (IE/IM ratio). High IE/IM ratios indicated high membrane fluidity. The IE/IM ratio of rat neutrophils (0.50 +/- 0.048) increased after E. coli inoculation, reaching a maximum of almost 1.00 after 10-20 min and then returning to its starting value. Intravenous injection of heat-killed E. coli or E. coli-conditioned culture supernatants into rats induced a rapid increase of IE/IM ratios, which returned to initial levels after 20 min. The effect on membrane fluidity of in vitro neutrophil incubation with E. coli, heat-killed E. coli, or E. coli-conditioned culture supernatants was similar to that observed in vivo. Addition of 5 mM ethylenediaminetetraacetic acid (EDTA) did not affect neutrophil membrane fluidity. Addition of either 5 micrograms/ml cytochalasin B or 10(-5) M colchicine did not directly affect neutrophil membrane fluidity but did block the change observed following incubation with bacteria.