Sperm treatment with extracellular ATP increases fertilization rates in in-vitro fertilization for male factor infertility

Previous work from our laboratory has revealed that extracellular ATP is a rapid and potent activator of human sperm acrosome reaction and fertilizing ability. In the present study, we assessed the effects of in-vitro sperm i ncubation with ATP on fertilization and embryo development in couples under going in-vitro fertilization (IVF) for male factor infertility, Oocytes fro m 22 women undergoing ovulation induction were divided in two groups and in seminated in vitro either,vith selected spermatozoa from the corresponding partner suffering from male factor infertility pre-incubated with ATP (2.5 mM) for 1 h, or with spermatozoa incubated with 0.9% NaCl solution (control group). After insemination, fertilization was assessed by the presence of pronuclei and then by embryo cleavage. The fertilization rate in the group of oocytes inseminated with ATP-treated spermatozoa improved significantly with respect to the control group (65.7 versus 42.5%, P < 0.01). No signifi cant differences were observed in embryo cleavage and embryo quality. Embry os from both treated and control groups were transferred together in 20 tra nsfer procedures, and in two couples fertilization was not obtained. Nine p regnancies occurred: one biochemical, one miscarriage, and seven patients d elivered 9 healthy babies. Two pregnancies were twin with an overall pregna ncy rate of 40.9% per cycle and of 45% per transfer. In conclusion, the res ults of the present study demonstrate that, in humans, extracellular ATP in duces a significant increase of sperm fertilizing potential, as these findi ngs are a rationale for the use of ATP for in-vitro treatment of human sper matozoa during IVF.