Kinematic definition of ram sperm hyperactivation

Abstract

Although it is known that ram spermatozoa exhibit hyperactivated motilityunder capacitating conditions, quantitative analyses of the head and flagellarmovement of washed ram spermatozoa have not been published. Motile spermatozoawere recovered from semen by swim-up into HSOF medium, and their movement in30-&micro;m-deep chambers was videorecorded. Spermatozoa of interest wereidentified during tape playback (hyperactivated spermatozoa were identified byvisual assessment of flagellar movement) and sequential head and tail imageswere traced onto overhead projector film attached to the video monitor. Theflagellar movement characteristics beat angle (FBA), beat envelope (FBE) andcurvature ratio (FCR) were determined by first principles, and head centroidkinematics were determined using Cartesian methods. Hyperactivated spermatozoahad significantly higher FBA and FBE and significantly lower FCR values thannon-hyperactivated spermatozoa (all P&lt;0.0001). Thecentroid kinematic values were also found to be significantly different, andkinematic criteria for ram sperm hyperactivation were developed. Thesecriteria were refined by consideration of 60-Hz CASA-derived trajectories, andram sperm hyperactivation was defined by: VCL &gt; 250.0 &micro;m s<emph type="7">-1 and VSL &le; 100.0 m s<emph type="7">-1 and LIN &le; 30% and ALHmax &ge; 9.0&micro;m.