| Budget Amount *help |
¥4,120,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
Although bisphenol-A (BPA) used in the manufacture of polystyrene and epoxy resins is thought to be a potent endocrine disrupter in rodents, the detail effect on the reproductive function is still obscure. We have already reported that female rats treated with BPA neonatally showed regular estrous cycles at 60 days, and contained ovaries with follicles and corpora lutea. However, they had a few fetal swellings and abnormal swellings in the uteri on Days 10 and 18 of pregnancy. In the present report, uteri and oviducts were investigated in female rats of the T strain given 7 daily injections of 1 mg BPA from the day of birth. The BPA-treated rats showing regular estrous cycles around Day 60. In both the BPA-treated and control rats, the uteri formed deciduomata in response to uterine trauma given the 4 th day of a 7-day treatment with progesterone and estradiol in aduthood, but the resposne was smaller in the former than the latter. The number of ova ovulated in the oviduct at the first
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estrus after Day 60 was fewer in the BPA-treated rats than in the controls. The BPA-treated rats showed occlusion and disappearance of the INF, and inflammation in the epithlium and stromal tissue on Day 60. The rats with oviduct malformation often contained ova within the ovarian capsule, but not in the ampulla. The abnormality was not evident until Day 30 and occurred Day 40 onward. Female rats likewise treated with 0.01mg estradiol-17b showed normal estrus cycles and similar damages in the oviduct around Day 60. These findings indicate that the reduction of fetuses in the BPA-treated pregnant rats may be accounted, at least in part, for by the failure in transport of the ovum due to the malformation of oviducts, rather than to uterine response, eliciting estrogenic action of BPA. It is known that the oviduct malformation containing inflammation and adhesion in the INF is an important factor for female infertility in human. The present study may be one of useful models for evaluation of the effect of endocrine disruptors on the female reproductive disorder Less
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