Effect of estradiol-17[beta] during in vitro growth culture on the growth, maturation, cumulus expansion and development of porcine oocytes from early antral follicles

• Published in: Animal science journal 2015-03, Vol.86 (3), p.251
• Main Authors: Kubo, Naoko, Cayo-Colca, Ilse Silvia, Miyano, Takashi
• Format: Article
• Language: English
• Subjects: Animal reproduction; Hogs; Steroids
• ISSN: 1344-3941; 1740-0929
• DOI: 10.1111/asj.12283

Growing porcine oocytes from early antral follicles can acquire meiotic and developmental competence under suitable culture conditions, but at lower rates compared to full-grown oocytes. We postulated that estradiol-17[beta] (E2) supported the acquisition of meiotic and developmental competence as well as cumulus-expansion ability during growth culture. Growing oocytes from early antral follicles (1.2 to 1.5mm in diameter) were grown in vitro for 5 days in a medium containing 0, 10-7, 10-6, 10-5 or 10-4mol/L E2; after in vitro maturation, 35, 58, 47, 74 and 49% of oocytes matured to metaphase II, 25, 79, 77, 90 and 97% acquired cumulus-expansion ability, and 23, 54, 63, 89 and 64% were fully surrounded by cumulus cells, respectively. Following maturation, electro-stimulation was applied to the oocytes grown with 10-5mol/L E2. After 6 days of culture, in vitro-grown oocytes developed to the blastocyst stage at a rate similar to that for full-grown oocytes (31% and 40%, respectively). Therefore, we suggest that the use of E2 during growth culture improves the meiotic and developmental competence of oocytes, cumulus-expansion ability, and cumulus cell attachment to the oocytes.