title: Electron paramagnetic resonance spectroscopy for the investigation of the fluidity of human spermatozoa plasma membranes: a feasibility study.
abstract: Spermatozoal membrane perturbations may play a role in abnormal sperm functions. The objective of this investigation was to study the feasibility of measuring membrane fluidity of isolated human sperm by electron paramagnetic resonance (EPR) spectroscopy and to compare the order parameter of spectra obtained from the sperm plasma membranes of living sperm of fertile men with that of infertile men. Ejaculates of infertile and fertile men were washed and the spermatozoa labelled with 5-doxylstearic acid (5-DSA) and 16-doxylstearic-acid (16-DSA) (10 nmol per 4 x 10(7) sperm). The reporter group of 5-DSA partitions into the outer, hydrophilic part of the sperm plasma membrane, whereas that of 16-DSA is distributed in the inner hydrophobic part. The following results were obtained: (i) the lowest measurable cell count was 3.6 to 7 x 10(6) sperm and the interassay variance of the order-parameter s was < 1%; (ii) swim-up experiments revealed a higher fluidity of sperm with a higher percentage of motility; (iii) sperm membranes of infertile patients exhibited a decreased fluidity of their plasma membranes in the polar interface region of 5-DSA compared with volunteer semen donors and fertile men (P=0.002). No difference of membrane fluidity was found between the different groups using 16-DSA. It is concluded that EPR spectroscopy can be used to study the fluidity of sperm plasma membranes in fertile and infertile men.
authors.affiliation: Department of Dermatology, Klinikum d.J.W. Goethe-Universität Frankfurt, Germany. ochsendorf@em.uni-frankfurt.de
authors.forename: F R
authors.initials: FR
authors.lastname: Ochsendorf
authors.forename: D
authors.initials: D
authors.lastname: Rinne
authors.forename: J
authors.initials: J
authors.lastname: Fuchs
authors.forename: P
authors.initials: P
authors.lastname: Such
authors.forename: G
authors.initials: G
authors.lastname: Zimmer
mesh_terms: D000328:Adult; D002462:Cell Membrane / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D008560:Membrane Fluidity; D008875:Middle Aged; D015203:Reproducibility of Results; D013076:Sperm Count; D013094:Spermatozoa / Q000502:physiology*; D013696:Temperature