Effect of seminal plasma on capacitation and hyperactivation in human spermatozoa

Abstract

While hyperactivated motility is known to be a concomitant of capacitation, and a prerequisite for fertilization, the specific interdependence of capacitation and hyperactivation in human spermatozoa has not been investigated. This study was designed to determine the effect of seminal plasma contamination on the expression of hyperactivated motility and the relationship between hyperactivation and capacitation, since seminal plasma contains decapacitation factor(s). Seminal plasma was obtained by centrifugation of aliquots of liquefied semen layered over 1.5 ml 40.5% Percoll and mixed with human tubal fluid (HTF) medium containing 30 mg/ml human serum albumin (HSA) (HTF) to a final concentration of 5% (v/v) seminal plasma (SP). Motile spermatozoa were isolated from the remainder of the semen by swim-up into either HTF or SP medium. Samples were taken from each treatment immediately post-harvest (0 h) and after 60 min at 37 degrees C (1 h) for hyperactivation and capacitation assessment. The treatments were then divided into two portions, centrifuged and resuspended in either HTF or SP, giving HTF control and SP control treatments and two crossover treatments, 1 h HTF then 1 h SP (H/SP) and 1 h SP then 1 h HTF (SP/H). All tubes were incubated for a further 60 min at 37 degrees C before aliquots were taken for hyperactivation and capacitation assessments. Hyperactivation was estimated using an IVOS v10.6t (Hamilton Thorne Research, Beverly, MA, USA) 60 Hz CASA instrument, and capacitation was estimated using the chlortetracycline (CTC) method. The presence of seminal plasma in the capacitation medium for 60-120 min post-swim-up inhibited the development of hyperactivated motility. This inhibition was reversible, and was not prevented by preincubation for 1 h in HTF medium. There was no difference in the CTC binding patterns between treatments at 2 h, indicating that the capacitation-associated membrane changes were not affected by the presence of a low concentration of seminal plasma. There was no correlation between percentage capacitated and percentage hyperactivated spermatozoa for any treatment. Since the proportions of hyperactivated spermatozoa and capacitated spermatozoa were not related, we conclude that the processes leading to hyperactivation and to the membrane changes associated with capacitation are not tightly interlinked and consider this finding to be due to hyperactivated motility being associated with flagellar movement, while the CTC assay assesses changes in the Ca2+ levels of the sperm head plasma membrane.

Relationship between seminal plasma zinc concentration and spermatozoa–zona pellucida binding and the ZP-induced acrosome reaction in subfertile men

“…By contrast, in men with normal sperm morphology, defective ZPIAR is most likely to be due to subtle biochemical or molecular defects in ZP receptors, signal transduction pathways, inefficient cholesterol or zinc removal from the plasma membrane during capacitation, actin polymerization or acrosomal enzyme activation [36][37][38][39][40][41][42]. Several in vitro studies have shown that zinc and SP inhibit sperm capacitation, including hyperactivation and AR, as well as spermatozoa-ZP binding and penetration [17,[20][21][22]. The hyperactivation of capacitated spermatozoa was highly correlated with the ZPIAR [43].…”

“…It is possible that zinc binding to the sperm plasma membrane affects calcium influx through ion competition during capacitation. It is known that SP contains decapacitation factors, as the addition of SP to the culture medium inhibits sperm capacitation and hyperactivated motility, as well as spermatozoa-ZP binding and penetration in vitro [19][20][21][22]. The overall, evidence suggests that a high SP zinc concentration may have a negative impact on the ZPIAR.…”

In vitro effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential and motility of human spermatozoa

“…Sperm kinetic parameters evaluated included progressively (PRG) motile as well as non-progressive and immotile sperm, curvilinear velocity (VCL; a measure of the total distance travelled by a given sperm during the acquisition divided by the time elapsed); average path velocity (VAP; the spatially averaged path that eliminates the wobble of the sperm head); straight line velocity (VSL; the straight-line distance from beginning to end of track divided by time taken); beat-cross frequency (BCF; frequency of lateral head displacement), ALH (the mean width of sperm head oscillation) and the derivatives, straightness (STR = VSL divided by VAP x 100) and linearity (LIN = VSL divided by VCL x 100, departure of sperm track from a straight line). To be classified as hyperactivated (HYPA), a trajectory had to meet all of the 60 Hz SORT criteria [Mortimer et al, 1998], i.e., VCL ≥ 150 µm/s, LIN ≤ 50% and ALH ≥ 7µm.…”

Induced hyperactivity in boar spermatozoa and its evaluation by computer-assisted sperm analysis

“…For example, Neill and Olds-Clarke (1987) have shown in mouse sperm that hyperactivation proceeds in the absence of BSA while acrosome-related processes are not observed (chlortetracycline assay). On the other hand, Mortimer et al (1998) reported that hyperactivation of human spermatozoa is inhibited by 5% seminal plasma during capacitation in human tubal fluid whereas acrosome-related processes are observed (chlortetracycline assay). Intracellularly, however, both hyperactivation and the acrosome reaction seem to be triggered by the same signal (Ca 2þ ; Yanagimachi 1994) possibly supported by other second messengers (e.g.…”