The Effects of Pentoxifylline on Mouse Epididymal Sperm Parameters, Fertilization and Cleavage Rates after Short Time Preservation

Background: Pentoxifylline (PX) prevents cAMP breakdown by inhibiting the activity of the cAMP-phosphatase and presumably, stimulates sperm motion. Incubation with PX causes hyperactivation of sperm, an important step in achieving fertilization, and leads to changes in membranes associated with sperm capacitation.
Objective: The purpose of this study was to examine the effects of pentoxifylline on sperm viability, motility and fertilization rate after mouse sperm preservation.
Materials & Methods: Epididymal spermatozoa from adult NMRI mice were collected in T6 medium supplemented with 5% BSA and divided into four control and four experimental groups. The control groups included: (1) Fresh sperm sample (2) Preserved sperm sample at room temperature for 18 hours. (3) Preserved sperm sample at incubator 37°C for 18 hours. (4) Preserved sperm sample at 4°C for 18 hours. Experimental groups were the same groups after treatment with 3mmol/L PX. All the samples were assessed according to World Health Organization Criteria. Oocytes from superovulated NMRI female mice were inseminated in-vitro incubated sperm of all the control and experimental groups. After insemination and washing, the fertilization rate and cleavage rate were assessed by the presence of two pronucleus (2PN) and 2-cell stage embryos. To study the acrosomal reaction of control and treated spermatozoa transmission electron microscopy (TEM) technique was used.
Results: The results showed that addition of 3mmol PX to preserved mouse spermatozoa at 4 ºC and 37 ºC could increase the motility rate significantly (P<0.05) and also it could enhance abnormal morphology rate. Significant increase of fertilization rate was seen after preservation of treated sperm at 4 ºC (P<0.05), but there was not seen significant difference regarding cleavage rate comparing treated and non-treated spermatozoa (P>0.05). Studies with electron microscopy showed that addition of PX to the preserved spermatozoa prevent early acrosomal reaction.
Conclusion: The results of this study demonstrated that addition of pentoxifylline in mouse sperm samples after short time preservation can enhance the motility and fertilization rate, although it can enhance the abnormal morphology. It also can increase the number of intact sperm after preservation.