Development to the blastocyst stage of parthenogenetically activated in vitro matured porcine oocytes after solid surface vitrification (SSV)

• Published in: Theriogenology Vol. 66; no. 2; pp. 415 - 422
• Main Authors: Somfai, Tamás, Dinnyés, András, Sage, Dagmar, Marosán, Miklós, Carnwath, Joseph W., Ozawa, Manabu, Kikuchi, Kazuhiro, Niemann, Heiner
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.07.2006
• Subjects: Animals; Blastocyst; Blastocyst - physiology; cell cleavage; Cell Survival - drug effects; Cell Survival - physiology; Cells, Cultured; Cryopreservation - methods; Cryopreservation - veterinary; cytochalasin B; Cytochalasin B - pharmacology; embryo (animal); Embryo Culture Techniques - methods; Embryo Culture Techniques - veterinary; Embryo, Mammalian - physiology; Female; freezing; in vitro culture; IVM; Oocyte; oocytes; Oocytes - physiology; parthenogenesis; Porcine; Pregnancy; swine; Swine - embryology; Vitrification; Porcine; IVM; Vitrification; Oocyte; Blastocyst
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2005.11.023

The effects of solid surface vitrification (SSV) on viability and parthenogenetic development of in vitro matured (IVM) porcine oocytes was investigated in the present study. Cumulus-free IVM porcine oocytes were subjected either to SSV or SSV combined with a cytochalasin B (CB) pre-treatment (SSV + CB) or all steps of SSV but without cooling (toxicity control = TC; toxicity control with CB pre-treatment = TC + CB). Oocyte viability was evaluated by plasma membrane integrity and esterase activity measured by a combined staining with fluorescein diacetate, propidium iodide and Hoechst 33342. Surviving oocytes were parthenogenetically activated then cultured in vitro (IVC) for 6 days. The proportion of live oocytes after vitrification was significantly lower than that of the TC, TC + CB and the control groups, regardless of the CB pre-treatment. Treatment of oocytes with cryoprotectants did not decrease the rates of surviving oocytes. After activation of oocytes, the proportion of cleaved embryos was significantly higher in the SSV + CB ( P < 0.05) than that of the SSV group. Nevertheless, significantly more oocytes cleaved ( P < 0.05) in the TC, TC + CB and the control groups. On Day 6, the rate of blastocysts in the SSV and SSV + CB groups did not differ significantly. The number of oocytes developing to blastocyst and the mean number of blastomeres per embryo were significantly higher ( P < 0.05) in the TC, TC + CB and the control compared with that of the SSV and SSV + CB groups. To our knowledge, this is the first report on parthenogenetic development to blastocysts of porcine oocytes vitrified at the metaphase-II stage. Results indicate that the high concentrations of cryoprotectants were not harmful for in vitro development, and that CB pre-treatment may increase survival and development of SSV vitrified porcine oocytes.