生物谷報(bào)道：中山大學(xué)和美國(guó)南佛羅里達(dá)大學(xué)的研究人員表示,，年老婦女產(chǎn)生新卵子幾乎不可能,。
這項(xiàng)新的研究結(jié)果發(fā)表于2007年3月的Developmental Biology期刊中，且于4月26日的Nature中提出對(duì)于該項(xiàng)研究的評(píng)論,。這項(xiàng)研究的結(jié)果反駁了哈佛的Jonathan Tilly博士的研究小組所獲得的具爭(zhēng)議性之發(fā)現(xiàn),。
Tilly 的研究結(jié)果發(fā)表在2004年的Nature中，2005年又在Cell中發(fā)布了一篇后續(xù)研究結(jié)果,。他的研究結(jié)果挑戰(zhàn)了生物學(xué)的一條基本定律,，即包括女人在內(nèi)的哺乳動(dòng)物與生俱來(lái)只有一定的生命期間產(chǎn)生卵子。Tilly的研究組發(fā)現(xiàn)干細(xì)胞能夠從骨髓遷移到小鼠卵巢并產(chǎn)生新的卵子,。
此后,，其它的一些研究論文反駁了Tilly的驚人發(fā)現(xiàn)：小鼠終身能產(chǎn)生新卵子。現(xiàn)在,，南佛羅里達(dá)州大學(xué)的David Keefe博士和在中山大學(xué)任職的同事Lin Liu證實(shí),，沒(méi)有證據(jù)顯示婦女在出生后可以產(chǎn)生新卵子的假說(shuō)。
研究人員在從12名年齡在28到53歲的婦女獲得的卵巢細(xì)胞活組織切片中,，搜尋干細(xì)胞或者減數(shù)細(xì)胞分裂的標(biāo)志,。
雖然研究人員使用了最靈敏的方法，但始終未發(fā)現(xiàn)人類卵巢中有任何卵子干細(xì)胞存在的證據(jù),。這表明,，Tilly在小鼠中的發(fā)現(xiàn)不能推及到人類身上。
Keefe解釋說(shuō),，Tilly博士可能看到的只是很像卵子的非卵子細(xì)胞,；另外一種解釋就是由于小鼠卵子比人類婦女卵子更具彈性，因此小鼠身上的發(fā)現(xiàn)不適用于婦女,。
研究人員表示,，這項(xiàng)研究非常重要，因?yàn)樗隙藢?duì)婦女產(chǎn)生卵子問(wèn)題的經(jīng)典定律,。生育學(xué)傳統(tǒng)觀點(diǎn)認(rèn)為,，婦女出生時(shí)就已經(jīng)形成了她這一生中所有的卵子，在每次排卵過(guò)程中被一個(gè)一個(gè)釋放,。而到了更年期,，卵巢里幾乎沒(méi)有成熟卵子存在。
（編譯/姜欣慧） (資料來(lái)源 : biocompare)
英文原文：
No Evidence Older Women Generate New Eggs
5/8/2007
Source: University of South Florida Health
It is highly unlikely that older women generate new eggs, report researchers at the University of South Florida in collaboration with a center in China.
The USF study, published in the March 2007 issue of the journal Developmental Biology and highlighted April 26, 2007 in Nature, counters the controversial findings of reproductive endocrinologist Jonathan Tilly, PhD, and his team of Harvard scientists. Tilly’s work, published in 2004 in Nature with a follow-up study a year later in Cell, challenged the biological dogma that mammals, including women, are born with a limited lifetime supply of eggs. Tilly reported the discovery of stem cells capable of migrating from bone marrow to mouse ovaries and generating new eggs there. The research fueled hopes that a new treatment – such as bone marrow transplantation – might one day help older women regain their fertility.
Since then, other papers have refuted Tilly’s surprising finding that mice can produce eggs throughout their lives. Now, David Keefe, MD, professor and chair of Obstetrics and Gynecology at USF, and colleague Lin Liu, who also holds a post at Sun Yat-Sen University in Guangzhou, China, say they can find no evidence to support his hypothesis that women may generate new eggs after birth.
The USF researchers searched for markers of stem cells or of meiotic cell division in ovarian cells biopsied from 12 women between the ages of 28 and 53.
“Despite using the most sensitive methods available, we found no evidence of any egg stem cells in human ovaries, demonstrating that Dr. Tilly’s findings in mice do not apply to women,” Dr. Keefe said. “Dr. Tilly likely was seeing non-egg cells which resemble eggs. Another reason his findings do not apply to women could be because mice eggs are more resilient than women’s eggs. The bottom line is that women should not expect stem cell therapy to treat egg infertility or menopause in the foreseeable future.”
“This is a very important finding by a distinguished group of researchers and clinician-scientists at USF Health which affirms the traditional dogma of a finite period of fertility in women,” said Abdul S. Rao, MD, MA, DPhil, senior associate vice president for USF Health and vice dean for research and graduate affairs at the College of Medicine.
The traditional view of fertility holds that women are born with all their eggs and they are released one by one (occasionally two) at each ovulation. At menopause, few to no mature eggs are believed to remain in the ovaries.
- USF Health -
USF Health is a partnership of the University of South Florida’s colleges of medicine, nursing, and public health; the schools of basic biomedical sciences and physical therapy & rehabilitation sciences; and the USF Physicians Group. It is a partnership dedicated to the promise of creating a new model of health and health care. One of the nation’s top 63 public research universities as designated by the Carnegie Foundation for the Advancement of Teaching, USF received more than $310 million in research contracts and grants last year. It is ranked by the National Science Foundation as one of the nation’s fastest growing universities for federal research and development expenditures.
