2003 Fiscal Year Final Research Report Summary
Investigation of bovine ovarian follicular dynamics and development of in-vitro follicle culture system
| Project/Area Number |
13460136
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied veterinary science
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| Research Institution | Hokkaido University |
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Principal Investigator |
TAKAHASI Yoshiyuki Hokkaido University, Graduate School of Veterinary Medicine, Professor, 大学院・獣医学研究科, 教授 (70167485)
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| Co-Investigator(Kenkyū-buntansha) |
NAGANO Masashi Hokkaido University, Graduate School of Veterinary Medicine, Instructor, 大学院・獣医学研究科, 助手 (70312402)
KATAGIRI Seiji Hokkaido University, Graduate School of Veterinary Medicine, Associate Professor, 大学院・獣医学研究科, 助教授 (00292061)
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| Project Period (FY) |
2001 – 2003
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| Keywords | cattle / ovarian follicle / ovulation / follicle culture |
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| Research Abstract |
This study was conducted to characterize bovine ovarian follicular dynamics during early postpartum period and to develop reliable in vitro follicle culture systems for investigating the mechanisms of folliculogenesis, oocyte growth, ovulation and ovarian dysfunction.
The postpartum resumption of follicular wave was observed around 4-6 days after calving in dairy cattle using ultrasonography. About 70% of the cows showed the first ovulation after one or two follicular waves, and the remaining cows ovulated after 3 to 11 waves. The cows with delayed first postpartum ovulation showed the delays in the resumption of FSH secretion and in the emergency of the first postpartum follicular wave. They also showed short first postpartum ovarian cycle due to the ovulation of dominant follicles of the first wave. By using transvaginal ultrasound-guided ovum pick-up technique, developmental competence of follicular oocytes and FSH/LH secretions during the early postpartum period were estimated.
To de
… More
velop reliable follicle culture systems, we employed mouse model and found the superiority of the follicle culture in membrane inserts. Using insert culture system, we obtained live pups originated from vitrified and in-vitro grown preantral follicles. More than 70% of mouse preantral follicles grown and ovulated in vitro after culturing in inserts and hCG treatment, and about 50% of in vitro ovulated oocytes developed to the blastocyst stage after in vitro fertilization. We used the follicle culture system to examine the role of growth factors in the follicular growth, and the results indicated that transforming growth factor-beta 1 is involved in follicular development and differentiation. It was also confirmed that bovine early preantal follicles cultured in collagen-gel could grow and yield the oocytes with maturational competence. These results demonstrate the usefulness of the present follicle culture system in the investigations of the follicular physiology and ovarian dysfunction. Less
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