[Electrofusion of two-cell embryos of rabbit and their developmental capacity in vitro]

Optimal conditions of electrofusion for blastomeres of rabbit two-cell embryos to produce tetraploid embryos were investigated. The high fusion rate (68.9-100%), viability and developmental capacity to morulae and blastocyst (74.5%), which was similar to the development rate (79.3%) of fertilized ova in vitro, were obtained under a electro-field strength of 2.0 kV/cm with direct current(DC) pulse of 40 microseconds duration. A non-electrolyte solution (0.3 mol/L Mannitol+0.1 mmol/L CaCl2+0.01 mmol/L MgSO4) used as electrofusion medium was much better than an electrolyte solution (DPBS). Cytological study showed that 72.7% of embryos exposed to electrofusion treatment had tetraploid chromosome sets at morulae and blastocyst stages. The optimal electrofusion parameters used in this study can be used in the technique of nuclear transplantation in rabbit embryos.