Successful implantation of in vitro-matured, electro-activated oocytes in the pig.

摘要

We derived parthenogenetic porcine fetuses from in vitro-matured oocytes following a simple activation process in order to evaluate their developmental limitations in vivo. Follicular oocytes collected from gilts at local slaughterhouses were matured for 48 h. They were subjected to a single square pulse of direct current for 100μsec at 1500 V/cm and then treated with 5μg/ml cytochalasin B for 4 h to obtain activated diploid oocytes. The diploids were cultured in modified Whitten's medium until transfer. Diploids which had cleaved to the 2- and 3- to 4-cell stages were transferred to oviducts of recipients. Live and/or dead parthenogenetic fetuses were recovered in 6 of 8 trials at 17, 18, 19, 24 and 29 days after activation. The total proportion of fetuses to transferred diploids was 31.3% (62/198). When fetuses were recovered at 19 days after activation, the proportion of development into fetuses was 71% (15/21). However, periods of gestation longer than 19 days resulted in a decrease of these proportions to 45% (18/40) at 24 days and to 18% (7/40) at 29 days. The hearts were beating in nearly all of the fetuses recovered at 19, 24 and 29 days after activation. Thus, parthenogenetic porcine diploids developed to at least the stage of limb-bud formation beyond the early heart-beating stage. Abnormalities were also externally visible on some fetuses. Formation of cyst-like structures in the heart and liver, and insufficient development of the head region and acephali were observed in some cases.