Studies On The In Vitro Maturation Of Porcine Oocytes And Their Subsequent Electric Activation

Effects of growth factors and hormones on the in vitro maturation of porcine oocytes were investigated, and meanwhile the electric parameters for activation of porcine oocytes were also explored in this study.(1) Addition of 10 ng/ml insulin like growth factor I (IGF-I) to the maturation medium resulted in significantly more porcine oocytes extruded the first polar body (PBl) (65.5% vs 43.3%, P <0.05) and developed to blastocysts (10.6% vs 3.8%, P<0.05) after parthenogenetic activation, although the cleavage rate did not change significantly.(2) Addition of 50 ng/ml EGF to the maturation medium resulted in significantly more porcine oocytes extruded PBl (66.9%, P<0.05) and developed to blastocysts (30.3% vs 19.2%, P<0.05) after parthenogenetic activation.(3) The effects of different hormones on in vitro maturation of porcine oocyte were investigated. Fewer oocytes cleaved when they were cultured in medium containing FSH in comparison with hMG. But the latter resulted in significantly more zygotes extruded PBl and developed to blastocyst stage after parthenogenetic activation.(4) Electric activation of porcine oocytes was explored in this study. Employment of 80 v/mm electronic field intensity resulted in significantly more blastocysts (15.1%)in comparison with 70 v/mm (9.8%)and 90 v/mm (3.6%)electronic field intensity. When electronic field intensity was fixed at 80 v/mm, 30 us and 50 us of pulse duration produced significantly more cleaved zygotes (77.6% vs 73.8%) and blastocysts (11.8% vs 11.7%)than 70 us group (61.5% vs 5.8%, P<0.05),although no significant difference was found between 30 us and 50 us group.In conclusions, (1) IGF-I and EGF can improve in vitro maturation of porcine oocyte, and the optimum concentration is 10 ng/ml and 50 ng/ml; (2)FSH is more efficient for in vitro maturation of porcine oocyte than hMG; (3) The superior electronic activation parameter for porcine oocyte is :80 v/mm, 30 μs~50μs.