The mechanics of hyperactivation in adhered human sperm

E. H. Ooi, D. J. Smith, H. Gadêlha, E. A. Gaffney, J. Kirkman-Brown

    Research output: Contribution to journalArticleResearchpeer-review

    14 Citations (Scopus)

    Abstract

    Hyperactivation is an important phenomenon exhibited by mammalian sperm during the process of acquiring fertilization capacity. The majority of studies have focused on incubation-induced hyperactivation in non-human species, which typically differ in size, shape, and are more homogeneous than human sperm. We develop an alternative approach via drug-induction, using high-speed imaging and analysis of same-cell changes in the flagellar movement of adhered cells. Following stimulation with 4-aminopyridine, approximately two-thirds (21 of 34) of the cells analysed exhibited a waveform with a single characteristic frequency; in all cases, the frequency was lower than before stimulation. The remaining cells (13 of 34) exhibited a more complex motility with multiple-frequency modes. The lowest mode in all cases was lower than the frequency prior to stimulation. Flagellar bending increased in all cells following stimulation and was significantly greater in the multiple-frequency responders. Despite the increased bending, time-averaged hydrodynamic power dissipation decreased significantly when assessed across all cells, the effect being significantly greater in the multiple-frequency responders than single frequency. These results reveal the heterogeneity of responses of human sperm to a hyperactivating stimulus, the methodology being potentially useful for assessing dynamic responses to stimuli in human sperm, and physiological selection of cells for assisted reproduction.

    Original languageEnglish
    Article number140230
    JournalRoyal Society Open Science
    Volume1
    Issue number2
    DOIs
    Publication statusPublished - Oct 2014

    Keywords

    • 4-aminopyridine
    • Binding
    • High-speed imaging
    • Sperm motility

    Cite this