KINEMATICS OF CAPACITATING HUMAN SPERMATOZOA ANALYZED AT 60 HZ

Hyperactivation is a concomitant of eutherian sperm capacitation, char acterized by the development of high amplitude flagellar waves with a corresponding increase in velocity. In humans, kinematic values have b een derived which describe the movement characteristics of spermatozoa analysed at 30 images/s. However, these values are frame rate-depende nt, and modern computer-aided sperm analysis (CASA) instruments used f or studying sperm movement now use 60 images/s. This study used first- principles manual track analysis to derive the range of movement chara cteristics which describe hyperactivated motility of human spermatozoa at 60 images/s. Standard terminology for centroid-derived movement ch aracteristics, as recommended by the World Health Organization, was us ed, US-standard (NTSC) video recordings of capacitating human sperm po pulations were replayed using a noninterlaced freeze-frame video casse tte recorder, and individual tracks reconstructed on acetate overlays. Tracks were classified as either forward progressive or hyperactivate d based upon flagellar beating patterns, then reconstructed manually a t X3540 and analysed using both manual methods and basic geometric cal culations from (x, y) coordinates (Cartesian methods) similar to those used by CASA instruments, In all, 40 hyperactivated and 40 forward pr ogressive tracks were studied, A set of Boolean arguments defining hyp eractivated motility was derived, and there was generally good agreeme nt between the limits derived by manual and Cartesian methods, The lim its for the definition of hyperactivated motility of human spermatozoa at 60 Hz derived by Cartesian methods were: curvilinear velocity grea ter than or equal to 180 mu m/s AND linearity less than or equal to 45 % AND wobble <50% AND amplitude of lateral head displacement ALH(mean) >6.0 mu m OR ALH(max) >10.0 mu m. The same limits were derived by man ual methods, except for ALH(max) >7.0 mu m. It is suggested that the m anually derived limits be applied in CASA instruments which use adapti ve smoothing programs to derive the average path.