| To examine the effect of Vascular Endothelial Growth Factor (VEGF) on the development of bovine oocyte in vitro, human recombinant VEGF165 was employed in a total of 11 experiments. Firstly, to determine whether VEGF increases the developmental potency of bovine oocytes matured in vitro (IVM) and/or fertilized in vitro (IVF) embryos, cumulus oocyte complexes (COC) of Holstein in Exp. 1 and Japanese Black in Exp. 2 were matured (n = 20 ?2 per drop) for 22 h in modified Synthetic Oviduct Fluid medium (mF), fertilized in BO for 6 h and cultured in vitro for 42 h (IVC1, 48 h Postnsemination; P1) in mOF with 0 (control), 0. 1, 1 and 10 ng/ml VEGF in Exp. 1 and 2 respectively. The rates of cleavage and development to 4?to 8ell embryos were examined at 48 h P1. The results demonstrated that the rates of cleavage and development to the 4-to-8-ell embryos were increased significantly by supplement 1 and 10 ng/ml VEGF in culture media during JVM, IVF and IVCI (P(0.05). Cleavage rates of Holstein vs Japanese Black embryos were 41. 5, 44. 7, 61.8 and 55.6% vs 47. 3, 51.4, 72.6 and 68.5% for 0, 0. 1, 1 and 10 ng/ml VEGF, respectively, and the rates of development to 4?to 8-ell stage of Holstein vs Japanese Black embryos were 24. 1, 23. 4, 41. 1 and 36. 1% vs 32. 0, 36. 4, 59. 7 and 52. 9% for 0, 0. 1, 1 and 10 ng/ml VEGF, respectively. Secondly, in order to select the optimum concentration of VEGF, 1, 2 or 5 ng/ml VEGF was supplemented in culture media during IVM, IVF and IVC1 in Exp. 3 based on the results of Exp. 1 and 2. The rates of cleavage and development to 4?to 8-ell stage embryos were elevated significantly in 1, 2 and 5 ng/ml VEGF-reated groups, respectively. However, there is no significant difference among these treatment groups (cleavage rates and development rates to the 4?to 8-ell stage were 49. 1, 48. 5 and 48. 7%, vs 42. 7, 42. 7, 45. 1% for 1, 2 and 5 ng/ml VEGF, respectively). The supplemented concentration of 5 ng/ml VEGF was selected for the further experiments to obtain more 4?to 8-ell embryos. Thirdly, to investigate the effective stage of the VEGF addition on the DIM, JVF and in vitro development to the blastocyst in the cow, a total of 6 experiments were conducted. To examine the effect of VEGF on the maturation of bovine oocytes, 5 ng/ml VEGF was employed in following 3 experiments. In Exp. 4, COG were matured for 22 h in m-F with 0 (control) or 5 ng/rnl VEGF. Maturation rate was increased from 78. 2% of the control to 90.5% (P(O. 05). In Exp. 5, COG were matured and inseminated with or without VEGF in each, the fertilization rate was improved from 63. 4% (control) to 79.8% or 82.3% with VEGF during maturation and both maturation and fertilization, respectively (P(0.05). In Exp. 6, CCC were matured as same as Exp. 4, then inseminated and cultured for 162 h in mOF without VEGF. Cleavage rate and development rate to 4?to 8-ell stage were examined at 48 h P1 and development rate to the blastocyst stage was examined at 168 h Pi. The cleavage rate and development rates to 4?to 8-ell stage and to blastocyst were significantly higher (82. 0%, 70. 3% and 45. 1%) than those of the control (67.5%, 52.5% and 33.3%, respectively; P(O.05). These results indicate that VEGF has a beneficial effect on the acquisition of the developmental potency of bovine oocytes during in vitro maturation. 2. Three experiments were conducted to determine the effect of V...
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