2001 Fiscal Year Final Research Report Summary
Development of an efficient methods of calf reproduction by embryo transfer in combination with treatment of interferon-_τ
| Project/Area Number |
11556054
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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 | 展開研究 |
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| Research Field |
Applied animal science
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
OKUDA Kiyoshi Okayama University, Graduate School of Natural Science and Technology, Professor, 大学院・自然科学研究科, 教授 (40177168)
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| Co-Investigator(Kenkyū-buntansha) |
NOGAMI Yoshiro Okayama Pref. Inst of Anim.Sci., Chief Researcher, 専門研究員(故人)
NIWA Koji Okayama Univ., Faculty of Agriculture, Professor, 農学部, 教授 (40089115)
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| Project Period (FY) |
1999 – 2001
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| Keywords | cattle / endometrium / tumor necrosis factor-α / PGF2α / oxytocin / IFN-τ / pregnancy / luteolysis |
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| Research Abstract |
The present studies indicate the presence of functional tumor necrosis factor-α (TNFα) receptors in the bovine cyclic endometrium and suggest a possible role of TNFα in the regulation of endometrial PGF_<2α> production in cattle. TNFα stimulated PGF_<2α> production only in the stromal cells via the activation of PLA2 and nitric oxide synthase. Moreover, TNFα increases COX-2 mRNA in bovine endometrial stromal cells. Since the expression of TNFα mRNA has been found only in epithelial cells in bovine endometrium, we assume that TNFα may play a role as a paracrine factor for the regulation of endometrial function. Although both OT and TNFα affected PGF_<2α> output at the follicular stage, TNFα, in contrast to OT, also affected PGF_<2α> output at the mid- and late luteal stages. Furthermore, since PGF_<2α> is produced preferentially by epithelial cells, we assume that TNFα-induced PGF_<2α> output from stromal cells is the first component of an auto-amplification cascade within the bovine en
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dometrium and switches on the positive feedback loop between the epithelial PGF_<2α> and the luteal OT to completes luteolysis. Finally, we have found that IFN-τ reduced TNFα-induced PGF_<2α> synthesis by bovine endometrial stromal cells in a dose-dependent manner. IFN-τ may inhibit luteolysis by reducing PGF_<2α> output by endometrial stromal cells.
An in vivo study was also conducted to determine the effects of trophoblastic interferon (IFN-τ, a type I IFN) on endometrial prostaglandin (PG) F2α secretion, luteal progesterone secretion and body temperature. Cows were treated twice a day from Day 14 to Day 17 after estrus with intrauterine injections of either control regimen (BSA) or recombinant bovine IFNα (a type I IFN). On Day 17, plasma concentrations of 13,14-dihydro, 15-keto-prostaglandin F2α (PGFM) were measured before and after injection of oxytocin. Plasma progesterone concentrations were measured during the estrous cycle. Rectal temperatures were measured twice a day from Day 14 to Day 17. Cows treated with IFNα had longer estrous cycle than control cows, although plasma progesterone concentration was not altered during treatment period of IFNα. A hyperthermic response was noticed after administration of IFNα on Day 14. Treatment with IFNα attenuated the oxytocin-induced increase in plasma PGFM. Less
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