Extracellular ATP and dibutyryl cAMP enhance the freezability of rat epididymal sperm

Hideaki Yamashiro, Masaaki Toyomizu, Natsuki Toyama, Nobuya Aono, Masahiro Sakurai, Yuuki Hiradate, Masaki Yokoo, Stefan Moisyadi, Eimei Sato

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)


    We studied the effects of ATP, ionomycin, and dibutyryl cAMP (dbcAMP) on the motility, freezability, and oxygen consumption of rat epididymal sperm. In vitro fertilization and intrauterine insemination were performed by using frozen-thawed rat sperm. Frozen-thawed sperm diluted in raffinose-modified Krebs-Ringer bicarbonate solution-egg yolk extender containing 1.85 mM ATP and 100 μM dbcAMP exhibited considerably higher motility and viability than sperm diluted in dbcAMP-free extender. Addition of ionomycin and dbcAMP to ATP-containing extenders did not alter the oxygen consumption rate of sperm, suggesting that extracellular ionomycin and dbcAMP are not involved in the mobilization of mitochondrial energy substrates in sperm. Further, high rates of pronucleus formation and progression to the blastocyst stage were observed in embryos produced by the fertilization of oocytes with fresh sperm in an in vitro fertilization medium supplemented with ATP and dbcAMP. Oocytes were not penetrated by frozen-thawed sperm when cocultured with cumulus-oocyte complexes in a medium without ATP and dbcAMP. In contrast, cryopreserved sperm penetrated oocytes when the gametes were cultured in an ATP- and dbcAMP-containing medium, and the resultant embryos formed blastocysts. Our results show that the dilution of rat sperm in raffinose-modified Krebs-Ringer bicarbonate solution-egg yolk extender supplemented with ATP and dbcAMP prior to sperm cryopreservation enhances the freezability of the cryopreserved sperm. Furthermore, the in vitro fertilization medium we developed effectively supports the production of embryos from both fresh and cryopreserved rat sperm.

    Original languageEnglish
    Pages (from-to)167-172
    Number of pages6
    JournalJournal of the American Association for Laboratory Animal Science
    Issue number2
    Publication statusPublished - 2010 Apr 15

    ASJC Scopus subject areas

    • Animal Science and Zoology


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