Parthenogenetic development of rabbit oocytes after electrical stimulation

The aim of this study was to determine the effect of electric pulses on the structural and functional condition of rabbit oocytes. The New Zealand White female rabbits at 3-5 months of age and at 3-4 kg body weight served as oocyte donors. Oocytes after flushing from the oviducts were placed between two electrodes in an electroporation chamber which was filled with a dielectric solution. Following a short incubation in B2 medium, oocytes were subjected to an electric pulse released by an electrical pulse generator. Oocytes were then incubated in 500 µl of B2 medium supplemented with 20% foetal calf serum (FCS) at 38°C in an atmosphere of 5% CO2 in air. Oocytes were cultured until the morula/blastocyst stage (approx. 72 h). The experiment was conducted using 430 oocytes obtained post mortem. In vitro cultured oocytes not subjected to an electric pulse were the control. Each group was subdivided into replications according to electric current intensity. The analysis of experimental variants shows that in the first variant all embryos developed to the morula stage but only 10% of them continued to develop to the blastocyst stage. In the second variant we observed that 5-10% of oocytes developed to the blastocyst stage after treatment with 2.0 and 2.5 kV/cm pulse but in the group of 1.0 kV/cm pulse 35% of oocytes developed only to the 2-12 b stage. In the third variant only 1 oocyte (5%) continued to develop to the blastocyst stage, but in the fourth variant oocyte development stopped at the morula stage. In the fifth variant, called an "extreme" one, oocytes stopped to develop at the stage of 2-12 b (about 25%) and the percentage of degenerated oocytes dramatically increased (about 60%).