Developmental capacity of vitrified immature porcine oocytes following ICSI: effects of cytochalasin B and cryoprotectants.
In the present study, effects of concentration and pretreatment time of cytochalasin B (CB), and of two types of cryoprotectant solutions on the nuclear maturation of vitrified-warmed porcine oocytes were examined. Also, the developmental capacity of vitrified immature porcine oocytes following intracytoplasmic sperm injection (ICSI) was investigated. The nuclear maturation rate (46.8%) of the vitrified-warmed oocytes treated with 7.5 microg/mL CB for 30 min was significantly higher (P < 0.05) than those (13.9-39.2%) of the vitrified-warmed oocytes treated with 0, 2.5, or 5.0 microg/mL CB for 10 or 30 min. Additionally, the nuclear maturation rate of oocytes treated with CB and vitrified in ethylene glycol (EG) (37.1%) was significantly higher (P < 0.05) than that of EG + dimethyl sulfoxide (Me(2)SO) (23.9%). However, no significant differences were observed in the cleavage and blastocyst development rates among the control (45.2 and 20.0%, respectively), the EG group (37.8 and 13.5%, respectively) and the EG + Me(2)SO group (39.3 and 14.3%, respectively). These results demonstrated that: (1) pretreatment with 7.5 microg/mL CB was beneficial for the vitrification of immature porcine oocytes; (2) the combination of EG and Me(2)SO as a cryoprotectant was not advantageous for in vitro maturation (IVM) of vitrified immature porcine oocytes; and (3) vitrified-warmed porcine oocytes matured after IVM, developed to the blastocyst stage without distinct differences compared to fresh oocytes following ICSI.
Fujihira
Takuma
T
Laboratory of Animal Reproduction, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Japan.
Kishida
Rie
R
Fukui
Yutaka
Y
D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D046508:Culture Techniques / Q000379:methods*; D003571:Cytochalasin B / Q000737:chemistry; D005260:Female; D009865:Oocytes / Q000378:metabolism / Q000473:pathology*; D010053:Ovary / Q000378:metabolism; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013552:Swine; D013696:Temperature
D003451:Cryoprotective Agents; D003571:Cytochalasin B