| Project/Area Number |
07456131
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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 |
Basic veterinary science/Basic zootechnical science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HAYASHI Yoshihiro The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (90092303)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Kenji The University of Tokyo, The Institute of Physical and Chemical Research, Labora, 動物試験室, 研究員 (50251418)
KUROHMARU Masamichi The University of Tokyo, Graduate School of Agricultural and Life Sciences, Asso, 大学院・農学生命科学研究科, 助教授 (00148636)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 1996: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1995: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | field vole / spermatozoa / IVF / zona pellucida / hypotaurine / insemination / acrosome reaction / zona-hydrolysing enzyme |
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| Research Abstract |
First, we tried to establish the in vitro fertilization (IVF) technique of the Japanese field vole. It is improved by sperm concentration (1-2x10^7 cell/ml for preincubation and 1x10^6 cell/ml for insemination) and hypotaurine (0.1-1 mM). Preincubation of spermatozoa with 1 mM hypotaurine pripor to oocytes insemination did not have a significant effect on fertilization rate. At 96 h after insemination, most cultured embryos developed to the 2-cell stage (68-83%), but development to blastocyst was very low (0-3%) for all treatments. Althogh 43 living offspring were produced after transfer of IVF pronuclear embryos to recipients, the delivery rate of recipients was very low (21%). The litter size of pseudopregnat recipients that produced a litter was 4 to 11, and the rate of in vitro development of transferred embryos in the pregnant recipients was 41%. It would appear that hypotaurine affects IVF rather than spermatozoa preincubation and that IVF embryos can develop to normal offspring. Next, we investigated the mechanism of penetration by field vole spermatozoa of mouse and hamster zonae pellucidae. The field vole spermatozoa that can penetrate the zonae pellucidae of the mouse and hamster could not penetrate the zonae of the rat, mastomys and Mongolian gerbil. The vole spermatozoa that bound to the zona oaf field vole oocytes underwent the acrosome reaction before passing through it. In contrast, the vole spermatozoa that bound to the zonae of mouse and hamster oocytes penetrated the zonae without any sign of the acrosome reaction. The presence or absence of proteinase/hyaluronidase inhibitors in the medium did not make any difference to zona penetration by acrosome-intact vole spermatozoa. These observations suggest that field vole spermatozoa can cross mouse and hamster zonae mechanically without assistance from zona-hydrolysing enzymes.
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