Bovine Oocytes in Secondary Follicles Grow in Medium Containing Bovine Plasma after Vitrification

• Published in: Journal of Reproduction and Development Vol. 57; no. 1; pp. 99 - 106
• Main Authors: TAKETSURU, Hiroaki, TAKAJO, Asuka, BAO, Rong-Mei, HAMAWAKI, Atsushi, YOSHIKAWA, Motoichi, MIYANO, Takashi
• Format: Journal Article
• Language: English
• Published: Japan THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT 2011
• Subjects: Animals; Blood Proteins - adverse effects; Blood Proteins - metabolism; Bovine; Breeding - methods; Cattle - physiology; Cell Size; Cryopreservation - veterinary; Culture Media - chemistry; Female; Follicle Stimulating Hormone - adverse effects; Follicle Stimulating Hormone - metabolism; Follicular Fluid - metabolism; Granulosa Cells - cytology; Granulosa Cells - physiology; Oocyte growth; Oocytes - cytology; Oocytes - physiology; Oogenesis; Organ Culture Techniques - veterinary; Organ Preservation - adverse effects; Organ Preservation - veterinary; Osmolar Concentration; Ovarian Follicle - cytology; Ovarian Follicle - physiology; Plasma; Secondary follicle; Time Factors; Vitrification
• ISSN: 0916-8818; 1348-4400
• DOI: 10.1262/jrd.10-047H

There has been no culture system that supports the growth of bovine oocytes for more than 2 weeks. In the present study, bovine secondary follicles were cultured for 4 weeks, and the effects of supplemented protein components and FSH in the culture medium on the growth of the oocytes were examined. The effect of vitrification of secondary follicles on the subsequent oocyte growth was also examined. Secondary follicles (150 to 200 μm in diameter) containing growing oocytes (approximately 60 μm in diameter) were dissected from ovaries and cultured in a medium supplemented with FSH (0, 25 or 50 ng/ml) and one of the following four kinds of protein components: bovine serum albumin (BSA), bovine plasma (BPL), fetal calf serum (FCS) and bovine follicular fluid (BFF). In BSA- and BPL-supplemented media with 0 or 25 ng/ml FSH, more than 50% of follicles showed no degenerative signs during culture, and oocytes significantly increased in size after 4 weeks (P<0.05). Higher percentages of granulosa cell-enclosed oocytes were recovered from the follicles cultured in BPL-supplemented media with 0 and 25 ng/ml FSH, and the oocytes grew to 90 μm or more in diameter. In FCS- and BFF-supplemented media, FSH increased the numbers of degenerating follicles. Next, vitrified-warmed secondary follicles were cultured in BPL-supplemented medium. One third of the follicles showed no degenerative signs, and the oocytes increased in diameter to 88.8 ± 3.1 μm after 4 weeks of culture. These results suggest that a BPL-supplemented medium supports oocyte growth in bovine secondary follicles for 4 weeks, even after vitrification and warming of the follicles.