302 EFFECT OF GROWTH DIFFERENTIATION FACTOR 8 ON PORCINE OOCYTE IN VITRO MATURATION AND SUBSEQUENT EMBRYONIC DEVELOPMENT AFTER PARTHENOGENETIC ACTIVATION AND IN VITRO FERTILIZATION

Abstract

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β that has been identified as a strong physiological regulator. The purpose of this study was to investigate the effects of GDF8 on in vitro porcine oocytes maturation and subsequent embryonic development after pathenogenetic activation (PA) and in vitro fertilization (IVF). We investigated nuclear maturation, intracellular glutathione (GSH), reactive oxygen species (ROS) levels, sperm penetration (SP) analysis, and subsequent embryonic development after PA and IVF. Each concentration (0, 1, 10, and 100 ng mL^–1) of GDF8 was added in maturation medium during process of in vitro maturation. Data were analysed by ANOVA followed by Duncan using SPSS (Statistical Package for Social Science) mean ± s.e.m. After 44 h of IVM, no significant difference was observed on nuclear maturation from the different concentration (0, 1, 10, and 100 ng mL^–1) of GDF8 treatment groups (85.5, 85.9, 89.4, and 87.6%, respectively) compared with the control (P > 0.05). The 10- and 100-ng mL^–1 GDF8-treated groups showed a significant (P < 0.05) decrease in intracellular ROS levels compared with other groups. The embryonic developmental competence after PA was affected with GDF8 treatment during IVM. The 10- and 100-ng mL^–1 treatment groups showed significantly (P < 0.05) higher cleavage rates (67.5 and 69.1%, respectively) compared with control group (53.7%). The 10- and 100-ng mL^–1 treatment groups also showed significantly (P < 0.05) higher blastocyst formation rates (50.5 and 52.7%, respectively) compared with other groups (34.5 and 35.8%). The IVF embryonic developmental competence also was affected with GDF8 treatment during IVM. The 10-ng mL^–1 treatment group showed a significantly (P < 0.05) higher blastocyst formation rates and total cell number compared with control (21.5 and 131.3 v. 15.0 and 92.6%, respectively). Also, in the sperm penetration assessment, the 10- and 100-ng mL^–1 treatment groups showed higher mono spermy ratio and fertilization efficiency (32.7 and 27.1, 32.0 and 26.5 v. 22.6 and 19.7%, respectively) than control, which was significant (P < 0.05). In conclusion, the treatment with 10 ng mL^–1 of GDF8 during IVM improved the PA and IVF porcine embryo developmental competence by decreasing the intracellular ROS levels.

This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2013R1A2A2A04008751), Republic of Korea.