Development of bovine ovarian activation and improvement of fertility by inhibiting the Hippo signaling pathway

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K08048
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Animal production science
• Research Institution: Miyagi University
• Principal Investigator: Kobayashi Jin 宮城大学, 食産業学群(部), 教授 (40234827)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 卵胞活性化 / 卵胞発育 / 卵巣断片化培養 / Hippoシグナル / 二次卵胞 / OPU / 卵巣穿刺刺激

Outline of Final Research Achievements

In the present study, we aimed to develop a method for activating secondary follicles by suppressing Hippo signaling in cattle. When a culture of bovine fragmented ovary was performed, transfer of Yap into the nucleus and increase of actin polymerization in the cell was confirmed after 6 hours of culture, and suppression of the Hippo signaling pathway was confirmed. By the culture of fragmented ovary, CCN2 and Birc5 genes, which are cell growth factors downstream of Hippo signal, showed a non-significant increase tendency. In an ovarian puncture test using 4 heifers, the antral follicle count showed a tendency to increase after puncture stimulation, and the total number of follicles and the number of small follicles showed a peek at the second month (p<0.01). After 5 months, it returned to the level of the follicle count before puncture stimulation.
Inhibition of Hippo signal could be a useful treatment for activating secondary follicles.

Free Research Field

動物生殖学

Academic Significance and Societal Importance of the Research Achievements

雌牛の繁殖機能は加齢と共に低下するが、その原因の一つが卵巣中の発育途上の卵胞数の減少にあると考えられている。原始卵胞、一次卵胞、二次卵胞といった初期の卵胞ほど卵巣中の割合が高いことから、これらの卵胞を活性化して退行を抑えることができれば、卵巣中の胞状卵胞数の増加につながる。そこで、本研究では二次卵胞の活性化法を検討し、Hippoシグナルを抑制することで、二次卵胞を活性化できることが明らかとなった。本成果により雌牛の繁殖機能が向上し、過排卵処理による回収胚数の増加や、超音波ガイド経膣採卵（OPU）による胚盤胞の作出効率の改善が期待できる。