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Animal Bioresource in Japan

.: Home > Animal Bioresource in Japan > 2010 > Volume 59 Number 1 > Seiji KITO 1), Hiroko YANO 1), Yuki OHTA 2) and Satoshi TSUKAMOTO 1)

Superovulatory Response, Oocyte Spontaneous Activation, and Embryo Development in WMN/Nrs Inbred Rats

Seiji KITO 1), Hiroko YANO 1), Yuki OHTA 2) and Satoshi TSUKAMOTO 1)
1) Research Center for Radiation Protection, National Institute of Radiological Sciences, 2) Science Service
Abstract :

WMN/Nrs inbred rats have been widely used in radiation biology for years. However, their reproductive profile has never been examined. We examined various reproductive characteristics of WMN/Nrs inbred rats such as superovulatory response, oocytes spontaneous activation (OSA), and embryo development in vitro and in vivo. Superovulation was induced in 3- to 9-week-old females by injection of 150 IU/kg PMSG and 150 IU/Kg hCG by 48 h apart. Only 8- and 9-week-old animals superovulated averaging 31.4 and 43.9 oocytes, respectively, and superovulation did not depend on estrous cycle. Animals 3-7 weeks of age did not superovulate. Because Wistar strains have been known to show a high incidence of OSA, factors expected to affect OSA in WMN/Nrs, including the time interval of various steps from euthanasia to oocyte recovery, incubation media, estrous cycle, and anesthetic treatments, were examined. The time from animal euthanasia to oviduct excision was the only factor shown to affect OSA. We also compared in vitro and in vivo embryo developmental competence between embryos obtained by natural ovulation and superovulation. Although percent in vitro development of 2-cell embryos to blastocysts was similar for embryos obtained by natural ovulation (63.7%) and superovulation (69.7%), fetus development after oviductal transfer of 2-cell embryos was significantly lower in embryos obtained by superovulation than in those obtained by natural ovulation (60.2% vs. 87.5%, P=0.02). Our results provide important normative data regarding future applications of rat assisted reproductive technologies (ARTs) such as in vitro fertilization and cryopreservation in WMN/Nrs strain and may be applicable to other strains of laboratory rats.

Keywords :
embryo development, inbred WMN/Nrs rats, oocyte spontaneous activation, superovulation

Date Deposited : 11 Jan 2011 14:29

Last Modified : 11 Jan 2011 14:29

Official URL: http://www.jstage.jst.go.jp/article/expanim/59/1/59_35/_article

Volume 59, Number 1, - 2010 , ISSN 1881-7122 (online), ISSN 1341-1357 (print)

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