| Co-Investigator(Kenkyū-buntansha) |
UMAOKA Y Kyoto Univ, Dept of OB & GY, Assistant Prof, 医学部, 助手 (80223593)
NARIMOTO K Kyoto Univ, Dept of OB & GY, Assistant Prof, 医学部, 助手 (70228097)
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| Research Abstract |
In out laboratory, an in vitro model for implantation was developed using primary uterine organ cultures as the substrate. In this model, the embryos attached to the endometrial explants within 60 min. The percentage of embryo attachment to uterine strips cultured from pregnant mice on days 1 to 4 was low(0.0-15.0%). However by days 5 to 7, the percentage of attachment increased markedly(66.8-74.8%). These levels were significantly higher than those observed for pseudopregnant(0.0-18.0%) and human chorionic gonadotropin administered pseudopregnent mice(0.0-15.0%). When utero-tubal junction was ligated in the pregnant mice the rate of attachment on day 5 was significantly higher than that of the pseudopregmant mice(10.0%). Furthermore, the rate of attachment to the unligated uterus was kept in a high level(61.7-70.9%) on days 6 and 7, but not to the uterus ligated (3.2-19.4). The concentration of serum steroids had no effects on the rate of embryos attached to the uterus. These results suggested that endometrial receptivity appears on day 5 of pregnancy and an embryonic factor(s) is involved in the aquisition of receptivity by surface epithelium, but direct contact between the embryo and the endometrial epithelium is not essential. It is also indicated that the onset of receptivity in the endometrium is transient, and when embryo-endometrial interaction have not taken place, endometrial receptivity will be lost on day 6 of pregnancy.
Thus, a part of the characteristics of the embryo-endometrium interaction became clarified.
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