120 SUPPLEMENTATION OF VASCULAR ENDOTHELIAL GROWTH FACTOR DURING IN VITRO MATURATION OF PORCINE IMMATURE CUMULUS–OOCYTE COMPLEXES AND SUBSEQUENT DEVELOPMENTAL COMPETENCE AFTER PARTHENOGENESIS AND SOMATIC CELL NUCLEAR TRANSFER

Abstract

In the present study, pig cumulus–oocyte complexes were cultured in medium supplemented with different concentrations (0, 5, 50, and 500 ng mL^–1) of vascular endothelial growth factor (VEGF), and then the maturation and intracellular glutathione (GSH) concentration of oocytes were examined. In addition, the development of oocytes matured with different concentrations of VEGF after parthenogenetic activation (PA) or somatic cell nuclear transfer (SCNT) was observed. Although the maturation rate of oocytes was not affected by VEGF concentrations (81.13 ± 2.61%, 83.93 ± 1.97%, 82.14 ± 4.03%, 75.24 ± 2.68%, respectively), the intracellular GSH concentrations of oocytes matured with 5 and 50 ng mL^–1 VEGF were significantly higher (12.68 ± 0.08, 12.33 ± 0.53 pMol/oocyte, respectively) than those of oocytes matured with 0 or 500 ng mL^–1 VEGF (10.19 ± 0.66, 10.54 ± 0.54 pMol/oocyte, respectively). The blastocyst formation rates after PA of oocytes matured with 5 and 50 ng mL^–1 VEGF were significantly higher (58.99 ± 4.70% and 54.00 ± 1.09%, respectively) than that of oocytes matured with 0 or 500 ng mL^–1 VEGF (30.15 ± 4.52%, 34.79 ± 4.01%, respectively). Total cell number of PA blastocyst after oocytes matured with 5 and 50 ng mL^–1 VEGF was significantly higher (83.21 ± 4.89, 78.16 ± 6.15, respectively) than that of control and 500 ng mL^–1 VEGF (56.91 ± 4.78, 55.93 ± 3.89, respectively). Similarly, the blastocyst formation rate after SCNT of oocytes matured with 5 ng mL^–1 VEGF was significantly higher (14.54 ± 1.42%) than that of oocytes matured without VEGF (7.95 ± 1.44%). Total cell number of SCNT blastocyst after oocytes matured with 5 ng mL^–1 VEGF was significantly higher (67.83 ± 6.56) than control (48.09 ± 5.36). Fully cumulus cell expansion was significantly higher in the 5 ng mL^–1 VEGF treated group (85.37 ± 0.73%) compared with the control (58.89 ± 0.88%). In conclusion, adding 5 ng mL^–1 VEGF during IVM improved the developmental potential of PA and SCNT in porcine embryos by increasing the intracellular GSH level.