Induction of the acrosome reaction in human spermatozoa by a fraction of human follicular fluid

Abstract

Human ejaculated spermatozoa were washed through a Percoll gradient, preincubated for 10 hr in a defined medium containing serum albumin, and then induced to undergo rapid acrosome reactions by addition of human follicular fluid or a Sephadex G‐75 column fraction of the fluid. Induction by follicular fluid did not occur when the spermatozoa were preincubated for only 0 or 5 hr. The reactions were detected by indirect immunofluorescence using a monoclonal antibody directed against the human sperm acrosomal region. The percentage of acrosomal loss counted by transmission electron microscopy agreed with that counted by immunofluorescence. The apparent molecular weight of the Sephadex G‐75 fraction containing the peak of acrosome reaction‐inducing activity was 45,000 ± 4,200 (SD). The occurrence of physiological acrosome reactions was supported by: assessing motility (no significant loss of motility occurred during the treatment period when sperm were preincubated with bovine serum albumin), transmission electron microscopy (the ultrastructural criteria for the acrosome reaction were met), and zona‐free hamster oocyte binding and penetration (spermatozoa pretreated with the active fraction of follicular fluid, then washed and incubated with oocytes, showed significantly greater binding to and penetration of oocytes). The stimulation of the acrosome reaction by follicular fluid is apparently not due to blood serum contamination; treatment of preincubated spermatozoa with sera from the follicular fluid donors had no effect on the spermatozoa. The nature of the active component(s) in that fraction is currently being investigated.

EFECTO DEL FLUIDO FOLICULAR SOBRE LA CAPACIDAD DE UNIÓN A ZONA PELÚCIDA DE ESPERMATOZOIDES EPIDIDIMARIOS DE ALPACA (Vicugna pacos)

“…Anteriormente, se ha podido reconocer para otras especies que el fluido folicular favorece ciertas funciones asociadas con la capacidad fecundante como la movilidad y la reacción acrosomal (Yanagimachi, 1969;Tesarík, 1985;Suarez et al, 1986;Morales et al, 1989;Ravnik et al, 1990;Hansen et al, 1991;McNutt y Killian, 1991;Ravnik et al, 1992;McNutt et al, 1994;Cheng et al, 1998;Jeon et al, 2001;Thérien et al, 2001;Briton-Jones et al, 2001;Schuffner et al, 2002;Getpook y Wirotkarun, 2007;Esmaeilpour et al, 2014;Leemans et al, 2015). Estudios previos en nuestro laboratorio determinaron que el fluido folicular favorece la movilidad espermática en alpaca (Bravo y Valdivia, 2017).…”

SUBSTANCE P AND SS-Endorphin ACT AS POSSIBLE CHEMOATTRACTANTS OF MOUSE SPERM

“…Several sperm functions can be modified at the time of ovulation by diverse components of the oocyte microenvironment. Thus, follicular fluid can accelerate capacitation, stimulate the acrosome reaction [31], induce sperm motility [24], and attract the sperm chemotactically [4,5,10,28,40]. Only some substances presented in the follicular fluid; for example, heparin [32,33] and hormones [34][35][36]39], have been investigated as sperm chemoattractants.…”

Effects of Percoll Discontinuous Density Gradients vs SpermPrep II vs Sephadex G-50 Gel Filtration on Semen Parameters.

“…The discontinuous, four-layer Percoll gradient technique (Suarez et al 1986), modified for human semen (Check et al 1992) was used to separate one aliquot of semen from each specimen. In brief, an isotonic, 90% (v/v) solution of Percoll (Sigma Chemical Co., St. Louis, MO, USA) was prepared by adding lOX DPBS (Irving Scientific, Irvine, CA, USA) buffer.…”

“…In brief, an isotonic, 90% (v/v) solution of Percoll (Sigma Chemical Co., St. Louis, MO, USA) was prepared by adding lOX DPBS (Irving Scientific, Irvine, CA, USA) buffer. This solution was diluted with modified Human Tubal Fluid (HTF) medium, (modified with 0.05% Human Serum Albumin Fraction V), to produce 50%, 60%, 70% and 80% (v/v) Percoll solutions (Suarez et al 1986). Using a 15 ml disposable centrifuge tube, 1 ml of each solution was carefully layered one over another, starting with 80% at the bottom, then a layer of 70%, 60% and then 50% on the top.…”