Pentoxifylline improves in vitro fertilization and subsequent development of bovine oocytes

The purpose of this study was to examine whether pentoxifylline improves in vitro fertilization and developmental rates of bovine oocytes. In the first experiment, we examined the effects on the fertilization rate of various concentrations of pentoxifylline (0-7.5 mM) combined with heparin (10 IU/mL). In the second experiment, we examined fertilization cleavage and blastocyst rates after frozen-thawed spermatozoa, obtained from four different bulls, were incubated with heparin (10 IU/mL) with or without caffeine (5 mM) or pentoxifylline (5 mM). In the first experiment, a significantly higher fertilization rate was obtained in heparin containing 5 mM pentoxifylline compared to that in heparin alone or in heparin containing 7.5 mM pentoxifylline (86% vs 60% vs 64%, respectively). The percentage of monospermy in 5 mM pentoxifylline (81%) was significantly higher than in heparin alone (57%). In the second experiment, the interactions among Bulls A, B, C, and D; between treatments (pentoxifylline-with-heparin, caffeine-with-heparin and heparin alone), and between bulls and treatments were analyzed for the number of oocytes penetrated, monospermic oocytes, cleaved oocytes and blastocysts. Among bulls, there was a significant difference in the number of oocytes penetrated (P < 0.01), monospermic oocytes (P < 0.05), cleaved oocytes (P < 0.001), and blastocysts (P < 0.001). Between treatments, there was a significant difference in the number of oocytes penetrated (P < 0.001), monospermic oocytes (P < 0.01) and cleaved oocytes (P < 0.001). Interaction between bulls and treatments was observed for the number of oocytes penetrated (P < 0.05). Individually, for Bulls A, C and D, the numbers of oocytes penetrated and monospermic oocytes in pentoxifylline-with-heparin were significantly higher than in heparin alone. For Bull D, significantly higher results were obtained for the number of oocytes penetrated, monospermic oocytes, cleaved oocytes and blastocysts in pentoxifylline-with-heparin compared to caffeine-with-heparin and heparin alone (P < 0.05). These results suggest that treating sperm with 5 mM pentoxifylline in combination with heparin is effective for bovine in vitro fertilization and it that this treatment is effective even for bulls that produce low fertilization and blastocysts after sperm treatment with caffeine-with-heparin or heparin alone.