Emergency contraceptives affect sperm chemotaxis towards progesterone

GUIDOBALDI, HA; REGALADO, J; BAHAMONDES, L; GIOJALAS, LC

Melbourne

Congreso; 10th International Congress of Andrology; 2013

International Society of Andrology

Emergency contraceptives (EC) are chemicals to be used after unprotected sexual intercourse to prevent pregnancy. Ulipristal (UPA) is a new EC pill which is an antagonist/agonist of progesterone (P). The contraceptive effect of UPA was only observed if it is taken before fertilization since its mechanism of action interferes and delays the ovulation. Additionally, P not only modulates embryo implantation and pregnancy; however, also stimulates several sperm functions prior to fertilization, including the chemotactic navigation of spermatozoa. The latter is a mechanism that orientates the spermatozoa towards the egg. As an EC pill, UPA may also interact with spermatozoa in the female genital tract. The aim of the study was to evaluate whether UPA affects the chemotactic response of human spermatozoa mediated by P. Capacitated spermatozoa were incubated with or without several UPA concentrations (1-1000ng/ml) for 30 min and then exposed in a chemotaxis observation chamber to a gradient of 10pM P or culture medium as negative control. Sperm movement were recorded by a videomicroscopy system and the tracks analyzed by computer image analysis with ImageJ and SpermTrack software. When spermatozoa were previously incubated with any UPA concentration the chemotactic response towards P was significantly prevented in comparison to those sperm that were not in contact with UPA. In contrast, the pharmacological induction of the acrosome reaction was not affected by a previous incubation with UPA. These preliminary results suggest that UPA may interfere with the chemical guidance of spermatozoa to find out the egg.