Mol. Hum. Reprod. Advance Access originally published online on May 18, 2008
Molecular Human Reproduction 2008 14(7):387-391; doi:10.1093/molehr/gan031
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RANTES and human sperm fertilizing ability: effect on acrosome reaction and sperm/oocyte fusion
1Andrologic Unit, Department of Internal Medicine, University of LAquila, Blocco 11, Coppito 67100, Coppito, LAquila, Italy 2Department of Basic and Applied Biology, University of LAquila, Blocco 11, Coppito 67100, Coppito, LAquila, Italy
3 Correspondence address: Tel: +39-0862-368338; Fax: +39-0862-368342; E-mail: sandrof{at}univaq.it
β-Chemokine, regulated on activation and normally T-cell expressed and presumably secreted (RANTES), is present in both the male and female genital tract fluids where its levels increase in diseases related to infertility, such as endometriosis and male genital tract infections. β-Chemokine receptors (CCR3 and CCR5) are expressed on freshly ejaculated human sperm cells and a sperm chemoattractant effect for RANTES has been reported. No information exists on other possible roles of RANTES on sperm functions involved in the fertilization process. In the present study, the exposure of sperm suspensions to high concentrations of the chemokine, comparable to those observed in inflammatory diseases, significantly decreased the stimulatory effect exerted by progesterone on sperm/oocyte fusion, evaluated by means of the hamster egg penetration test. Accordingly, a large proportion of spermatozoa preincubated under capacitating conditions with high concentrations of RANTES underwent a premature acrosome reaction (AR) that prevented subsequent progesterone-induced AR. Finally, sperm samples exposed to the same high levels of chemokine showed a significant increase in the intracellular levels of cAMP, which is involved in capacitation and AR dynamics. These results indicate a negative interference of high levels of RANTES on the sperm fertilizing ability, thereby suggesting a potential contribution of this chemokine to subfertility associated with endometriosis and genital tract inflammatory diseases.
Key words: RANTES/fertilization/human spermatozoa/acrosome reaction/sperm/oocyte fusion
Submitted on February 13, 2008; resubmitted on May 9, 2008; accepted on May 13, 2008.