Transcriptional downregulation of ABC transporters is related to follicular degeneration after vitrification and in vitro culture of ovine ovarian tissue

Abstract

ATP-binding cassette (ABC) transporters perform multiple functions in reproductive tissues. During ovarian tissue vitrification, the plasma membrane has important functions in the influx or efflux of water, and substances such as cryoprotectants and channel proteins that are required in this process. Thus, the present study aimed to verify the relative abundance of mRNA transcript of ABC transporters ABCB1, ABCG2, and MRP2 after vitrification and in vitro culture (IVC) of ovine ovarian tissue. For this study, the ovarian cortex fragments were proportioned into four groups as fresh control, vitrified control, fresh culture, and vitrified culture groups. After vitrification and in vitro culture, the ovarian tissue was evaluated using morphological procedures. Further, relative abundance of ABCB1, ABCG2, and MRP2 transporter mRNA transcripts in the ovarian cortex subjected to aforementioned treatment conditions were evaluated using qPCR. Our results showed a negative association between degenerated follicles and mRNA transcript abundances of ABCB1 and ABCG2. In addition, the percentage of growing follicles in the ovine ovarian cortex after vitrification was similar to that of the fresh control tissue without in vitro culture. The in vitro culture of fresh and vitrified tissue however, showed a significant decrease in the percentage of growing follicles. To the best of our knowledge, we believe that our data for the first time has studied the relative abundances of ABCB1 and ABCG2 mRNA transcripts in the ovine ovarian cortex. In addition, alterations of these protein channels may be indicative of a deleterious effect of osmotic stress on follicular survival during vitrification. Furthermore, these effects were detectable only after the IVC of the ovarian tissues. Nonetheless, further studies are required to investigate the functions of ABC transporters in ovine folliculogenesis, especially after in vitro culture of ovarian tissue.