Received October 05, 2007
Accepted November 18, 2007

Objective:To evaluate the effect of Pentoxifylline(PTX) applied to freeze-thawed spermatozoa, on fertilization rates and embryo development after intracytoplasmic sperm injection (ICSI) cycles. Methods:This study included nine couples who underwent 21 assisted reproduction techniques by ICSI using frozen-thawed spermatozoa. After thawed, the sperm samples were processed by sperm-wash or swim-up, and divided into two equal aliquots.The first was treated with 5mM PTX solution (group PTX) for 30 minutes at 37ºC, and other without PTX (group CT). 145 oocytes in metaphase II(MII) were injected, 72 with spermatozoa of CT group, and 68 with PTX treated sperm.The fertilization rate, pro-nuclei morphology,early cleavage and embryo morphology on transfer day were evaluated. Results:PTX treatment didn’t improve the spermatozoa total motility(31,5%x34,2%,p=0,150 for PTX group and CT group,respectively) and the progressive motility (20.5% x23.4%;p=0.057,for PTX group and CT group,respectively).After ICSI, the normal fertilization rates, were 73.4% in the group PTX and 78.3% in group CT(p=0,516).The percentage of embryos presenting good pro-nuclei morphology (23.9%x25.0%;p=0.901,for PTX and CT,respectively) as well as early cleavage (27.7%x30.0%;p=0.925 for PTX and CT,respectively) were similar.Also, 48.9% of embryos on group PTX and 59.6% on group CT, presented good morphology on day +3(p=0.283).Embryos originated from ICSI using spermatozoa from both group I and group II were transferred, and a total of 8 pregnancies were achieved(pregnancy rate:38.9% and implantation rate:22,2%). Conclusion:It was observed that the treatment of spermatozoa with PTX, in comparison with nontreated group, had similar results in the total and progressive sperm motility and other embryo parameters evaluated.