研究者詳細 - 木村　康二

論文 - 木村　康二

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Effect of Vascular Endothelial Growth Factor on maturation, fertilization and developmental competence of bovine oocytes 査読

HL Luo, K Kimura, M Aoki, M Hirako

JOURNAL OF VETERINARY MEDICAL SCIENCE 64 ( 9 ) 803 - 806 2002年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN SOC VET SCI

To examine the effect of Vascular Endothelial Growth Factor (VEGF) on the maturation of bovine oocytes, human recombinant VEGF(165) was used in 3 experiments. In Exp. 1, bovine cumulus oocyte complexes (COCs) were matured for 22 hr in modified Synthetic Oviduct Fluid (m-SOF) supplemented with 0 (control) or 5 ng/ml of VEGF. Maturation rate increased (P<0.05) from 78.2% in the control to 90.5% in the VEGF treated group. In Exp. 2, bovine COCs were matured in m-SOF and co-incubated with sperm in modified BO medium, each supplemented with or without 5 ng/ml VEGF. Normal fertilization rate was improved (P<0.05) from 63.0% (control) to 79.8% or 82.3% with VEGF during maturation or both maturation and fertilization. In Exp. 3, bovine COCs were matured the same way as in Exp. 1, then co-incubated with sperm for 6 hr and cultured for 162 hr in m-SOF without VEGF. Cleavage rate and development rate to the 4- to 8-cell stage were examined at 42 hr post-co-incubation and development rate to blastocyst was examined at 162 hr post-co-incubation. Cleavage, the development to the 4- to 8-cell stage and blastocyst rates (82.0%, 70.3% and 45.1%, respectively) were significantly higher (P<0.05) in the VEGF group than those in the control (67.3%, 52.5% and 33.3%, respectively). These results indicate that VEGF has a beneficial effect on the maturation of bovine oocytes.

DOI： 10.1292/jvms.64.803

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Role of G6PD activity on sex ratio and developmental competence of bovine bnbryos under oxidative stress 査読

Hisataka Iwata, Koji Kimura, Syu Hashimoto, Maiko Ohta, Keiichirou Tominaga, Naojirou Minami

Journal of Reproduction and Development 48 ( 5 ) 447 - 453 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：The Japanese Society of Animal Reproduction (JSAR)

Inactivation of the X-linked gene in the female embryo is one of the major events during mammalian early embryogenesis. Before this inactivation, enzyme activity encoded by the X-linked gene is different between male and female embryos. In the present study, we demonstrated a possibility that there may be a different response to specific culture conditions in vitro between male and female early embryo. Glucose-6-phosphate dehydrogenase (G6PD) is one of the X-linked enzymes and its activity is semi-quantitated by brilliant cresyl blue (BCB). In experiment 1, the relationship between semi-quantitated G6PD activity and the sex ratio of the embryos was examined. In experiment 2, the relationship between semi-quantitated G6PD activity and the developmental competence of embryos was examined. No relationship was found between G6PD activity and sex in 8-cell, 16-cell and blastocyst stage embryos. However, G6PD activity was high in female embryos and low in male embryos at the morula stage. When morula stage embryos were categorized by BCB and cultured under high oxygen tension (5% CO2, 95% air), the developmental competence of embryos having high G6PD activity was higher than those having low enzyme activity. However, when the categorized morula stage embryos were cultured under low oxygen tension (5% CO2,5% O2, 90% N2), there was no difference in the developmental rates among the categories. These results indicate that G6PD activity is high in female morula stage embryos compared with that in male embryos, and that the activity of this enzyme strongly affects the developmental competence of morula stage embryo when they are cultured under high oxygen tension.

DOI： 10.1262/jrd.48.447

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Sexual dimorphism among bovine embryos in their ability to make the transition to expanded blastocyst and in the expression of the signaling molecule IFN-τ 査読

Melissa A. Larson, Koji Kimura, H. Michael Kubisch, R. Michael Roberts

Proceedings of the National Academy of Sciences of the United States of America 98 ( 17 ) 9677 - 9682 2001年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

IFN-τ is a secretory product of trophectoderm of cattle, sheep, and their relatives and is expressed for a few days in early pregnancy after the blastocyst first forms. It serves to alert the mother that she is pregnant. A delayed or less than robust IFN-τ signal is a likely cause of embryonic loss. Here we have determined whether blastocyst production of IFN-τ, which is encoded by a cluster of genes on chromosome 9, differs between the sexes in cattle, as assessed by culture of in vitro-derived embryos on two different media, one complex (tissue culture medium 199 supplemented with serum) with coculture support, the other relatively simple (synthetic oviductal fluid plus albumin). With both media, female blastocysts produced approximately double the amount of IFN-τ as males, regardless of such variables as oocyte batch, blastocyst quality, hatching, and length of time in culture. However, in either tissue culture medium 199, which contains 5.5 mM D-glucose, or in synthetic oviductal fluid, in the presence but not in the absence of added glucose, significantly fewer female than male embryos were able to progress from the morula/early blastocyst stage to more advanced stages of development. It is possible that the differences between male and female embryos both in their production of IFN-τ and in their ability to progress in development in glucose-rich media are manifestations of phenomena that occur in vivo and provide plasticity in embryo selection during early pregnancy.

DOI： 10.1073/pnas.171305398

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放牧における発情牛の歩行数の解析

植田直円, 青木真理, 木村康二, 加茂幹男, 伊吹俊彦, 砂原弘子

日本家畜管理学会誌 34 ( supplement ) 24 - 25 1998年

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