Fertilizability of Superovulated Eggs by Estrous Stage-independent PMSG/hCG
Treatment in Adult Wistar-Imamichi Rats |
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Authors: | Hiroe Kon Ryoji Hokao Motoo Shinoda |
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Institution: | 1)Laboratory Animal Research Center, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan;2)Institute for Animal Reproduction, 1103 Fukaya, Kasumigaura, Ibaraki 300-0134, Japan |
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Abstract: | We investigated the fertilization and developmental ability of superovulated eggs
obtained from adult Wistar-Imamichi (WI) rats, by using pregnant mare serum gonadotropin
(PMSG) and human chorionic gonadotropin (hCG) treatment. Female WI rats, 11–13 weeks of
age, were divided into four groups by estrous stage (metestrus ME], diestrus DE],
proestrus PE], or estrus E]). PMSG (150 IU/kg) and hCG (75 IU/kg) were injected at an
interval of 48 or 55 h and the female rats were mated with mature male rats. The ovulated
eggs were collected 20, 24, and 27 h after hCG injection. Regardless of the estrous stage
at the time of PMSG injection, the treated rats mated and ovulated similar to the
untreated spontaneously ovulated rats (S group). Although the proportion of fertilized
eggs in the E- and PE-treated groups was less than the S group 20 h after hCG injection,
the proportion was not different among all treated and S groups 24 h after hCG injection.
The proportion of fertilized eggs using in vitro fertilization and the
proportion of offspring obtained from 2-cell stage embryo transfer did not differ among
the treated and S groups. In comparison with PMSG/hCG-treated immature rats, mating and
ovulation rate of adult rats were significantly higher. The proportion of fertilized eggs
obtained from mated rats did not differ between immature and adult rats. These results
demonstrate that adult WI rats are good egg donors for reproductive biotechnological
studies using unfertilized or fertilized eggs. |
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Keywords: | adult rat estrous cycle fertilization superovulation |
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