Development of a transient co-incubation IVF system in the pig

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This research project was undertaken to develop a transient-co-incubation IVF system in the pig, in order to obtain an efficient normal monospermic sperm penetration. Obtained sights are as follows :(A)Effect of pretreatment of spermatozoa with adenosine and a transient gamete co-incubation with caffeineA new transient co-incubation IVF system, in which denuded oocytes are co-cultured with spermatozoa in medium containing caffeine for 5 to 30 min and then continuing the culture in caffeine-free medium, will reduce the incidence of polyspermic penetration. Preincubation of fresh spermatozoa with adenosine before the transient co-incubation IVF can also improve the monospermic penetration.(B)Effective regulation of sperm capacitation during transient IVF periodThe presence of beta-mercaptoethanol (bME) prevents induction of sperm capacitation even in the presence of caffeine, whereas H_2O_2 induces sperm capacitation and the spontaneous acrosome reaction.(C)Regulation of oxidative stress of gametes during transient co-incubationSupplementation with bME during IVF procedures, except during a transient co-culture period of gametes in the presence of caffeine, has a beneficial effect in maintaining the function of gametes, the incidence of normal fertilization and, consequently, the quality of IVF embryos.(D)Selection of antioxidants to improve the function of extended boar semen stored at a low temperatureGlutathione and cysteine can improve the viability and functional status of boar spermatozoa during liquid preservation and boar spermatozoa penetrated in vitro even after preservation in the presence of cysteine at 10℃ for 29 days.(E)Development of an IVM system for the transient IVF systemAlthough cytoplasmic maturation in porcine oocytes pretreated with roscovitine for 48 h did not equal that of control oocytes in the current IVM system, those stored oocytes can matured, fertilized and developed in vitro to the blastocyst stage.