Studies On The Electric Fusion Parameters For Porcine Somatic Cell Nuclear Transfer

In order to determine the appropriate electric fusion parameters for porcine somatic cell nuclear transfer, four experiments were conducted in the present study, in which in vitro matured porcine oocytes were used as recipients and porcine granulosa cells were used as donors.Effects of pulse intensity on the electric fusion were examined in Experimemt 1. The fusion rate in 0.77 kv/cm group (59.3%) were significantly higher than that in 1.54 kv/cm group (38.6%, P<0.05), but the cleavage rate and morula/blastocyst yield in 0.77 kv/cm (77.8%, 33.3%) were not significantly different (P>0.05) from those in 1.54 kv/cm group (75.0%, 31.3%), and only significantly higher than those of 2.31kv/cm group (52.2%, 13.6%) (P<0.05). Effects of pulse duration on the electric fusion were investigated in Experimemt 2. Pulse of 20 μs resulted in significant more couples of cytoplasts and donor cells fused (68.0%) in comparison with pulse of 30μs (42.7%) and 40μs (35.5%, P<0.05). The the cleavage rate and morula/blastocyst yield of 20 μs group (89.3%, 24.2%) were not different from those of 30 μs group (87.2% and 23.4%, P>0.05), but the cleavage rate was higher than that of 40 μs group (60.5%, P<0.05). Effects of pulse number on the electric fusion were investigated in Experiment 3. The fusion rate in one pulse group (72.8%) was higher than that in 2 pulses group (56.0%, P<0.05), although the cleavage rate and morula/blastocyst yield were similar between the two groups. Effect of alternating current on the electric fusion was examined in Experiment 4. Applying alternating current (1.0v) before direct current pulse did not affect the fusion rate (70.0% vs 76.0%), cleavage rate (77.3% vs 75.0%) and embryo development (17.3 % vs 18.4%).In conclusion, the appropriate electric fusion parameters for porcine somatic cell nuclear transfer are 0.77kv/cm of pulse intensity, 20 μs of pulse duration and 1 of pulse number.