The use of pentoxifylline to improve motility of cryopreserved equine spermatozoa

Pentoxifylline was evaluated as a method to increase motility of cryopreserved equine spermatozoa. In a preliminary experiment, pentoxifylline (3.5 mM or 7.0 mM) was added to extended semen that was chilled to 4 degreesC. Motility was evaluated at 8-h intervals for 48 h. The addition of 3.5 or 7.0 mM pentoxifylline appeared to increase the motility of chilled spermatozoa compared to controls. Based on these results, similar concentrations of pentoxifylline were added to semen either before or after cryopreservation. The addition of pentoxifylline (3.5 or 7.0 mM) to semen before cryopreservation significantly (P < 0.001) decreased total and progressive motility compared to controls. However, the addition of pentoxifylline (3.5 or 7.0 mM) to cryopreserved semen immediately after thawing significantly (P < 0.01) increased total and progressive motility compared to controls. These results indicate that pentoxifylline enhanced the postthaw motility of cryopreserved equine semen when added after thawing. Further research is required to evaluate the effect of pentoxifylline on the fertility of cryopreserved equine semen. (C) 2000 by Elsevier Science Inc.