In vitro effect of levonorgestrel on human sperm function

M.J. MUNUCE; J. NASCIMENTO; G. ROSANO; A. FAUNDES; L. BAHAMONDES

Praga

Otro; 22nd Annual Meeting of the European Society of Human Reproduction and Embryology; 2006

European Society of Human Reproduction and Embryology

Introduction: The levonorgestrel-releasing intrauterine system (LNG-IUS) exerts its contraceptive effect by interfering with sperm transport, ovulation and fertilization However, a direct effect of the steroid on sperm function cannot be discarded. The aim of this study was to evaluate whether LNG, at doses comparable to that measured in the uterus during the use of the LNG-IUS, affects the detection of D-mannose-binding sites or zona pellucida (ZP) receptors on human spermatozoa. The association with acrosomal status was also investigated. Materials and methods: Semen samples from normozoospermic donors were used for the study (n=17). Seminal plasma was removed by layering the semen on a Percoll gradient (90?50%). Motile spermatozoa were incubated under capacitating conditions for 22 h at 37 ºC under 5% CO2 in air. A stock solution of LNG was prepared by dissolving the hormone in ethanol (mg/ml). Capacitated spermatozoa were exposed to 1 or 10 ng/ml of LNG or control medium for 30 min. To exclude any toxic effect on sperm function, sperm viability was evaluated by eosin Y at the end of all procedures. D-mannose-binding sites were detected on sperm surface using D-mannosylated-BSA conjugated with fluorescein isothiocyanate (Man-FITC-BSA). Each spermatozoon was categorized according to the pattern of the fluorescent signal as follows: pattern I (tail and midpiece, unspecific), pattern II (whole acrosomal cap plus midpiece, specific) or III (equatorial/post equatorial plus midpiece, specific). Acrosomal status was analyzed using the Pisum sativum technique. Double labeling with Man-FITC-BSA and rhodamine-conjugated Pisum sativum agglutinin was also performed. Data were expressed as mean±SEM and were analyzed using the one-way ANOVA and the Tukey?Kramer test or the c2 test. A p-value74% viable cells). When capacitated spermatozoa were exposed to LNG a significant increase in the percentage of spermatozoa showing pattern III was observed with respect to controls (control: 25±5% vs. LNG; 1 ng/ml: 34±7%* vs. LNG; 10 ng/ml: 36±5%*, n=5, *p