Pentoxifylline potentiates ionophore (A23187) mediated acrosome reaction in human sperm: flow cytometric analysis using CD46 antibody

The study was designed to investigate the effects of pentoxifylline on the acrosome reaction of human spermatozoa in vitro, and to determine whether the reaction is differently modulated after sperm selection by multiple tube swim-up and Percoll buoyant density centrifugation. The acrosome reaction was induced in vitro by using calcium ionophore (A23187) and was detected by measuring the fluorescence of FITC-conjugated goat anti-mouse immunoglobulin bound to CD46 antibody (which binds to the CD46 receptor site on the inner acrosomal membrane) by flow cytometry. Spermatozoa separated on Percoll displayed significantly lower spontaneous acrosome reactions (P = 0.002) than did those separated by the swim-up technique. Pentoxifylline did not, by itself, induce acrosome reaction, but after induction with ionophore, it significantly increased the reaction (P = 0.003) and this increase was seen to be greater when Percoll separation was used as compared to the swim-up technique (P = 0.0002). We therefore conclude that Percoll selection of motile spermatozoa together with pentoxifylline treatment may be of value in assisted reproductive techniques, as an increased ARIC score arose after both treatments, and that flow cytometry allows a precise and rapid quantification of the acrosome reaction.