Reproduction Abstracts

Ganglioside is an acidic glycosphingolipid with sialic acid residues. The b-series ganglioside GT1b was reported that suppressing damage of mtDNA by reactive oxygen species (ROS) in mouse brain. The purpose of this study is to investigate the effect of exogenous addition of GT1b on in vitro maturation (IVM) of porcine oocytes and to confirm the related bradykinin 2 receptors (B2R). GT1b were treated on IVM that concentration was 0 (control), 5, 10 and 20 nM. After IVM, we evaluated intracellular ROS levels in matured oocytes. The 10 and 20 nM groups showed a significant (P<0.05) decrease in intracellular ROS levels compared with control group. To analyze the mechanism of GT1b effect on IVM, we identified the existence of B2R known to increase calcium concentration stimulated by GT1b. As a result, we identified the expression of B2R in cumulus cell but not in oocyte. To examine the expression of apoptosis-associated genes (Bax, BCl2, Caspase-3), B2R and CaMK2G gene in matured cumulus cells. The treatment of 20 nM GT1b significantly (P<0.05) decreased the expression of PCNA and CaMK2G, and BCl2, an anti-apoptotic gene, was increased significantly (P<0.06). GT1b significantly (P<0.05) decreased expression of B2R. In conclusion, these results indicated that GT1b may play an important role in decreasing the intracellular ROS levels during IVM. Further studies are needed to show the mRNA expression of apoptosis-associated genes and CaMK2G in matured oocytes. This work was supported, in part, by a grant from the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.