Subjects: R and D
Just weeks after scientists blew up the dogma that new heart muscle cells can’t be generated after birth, other investigators have followed suit for the eggs of mammalian females.
A familiar tenet of reproductive medicine held that women were on a biological clock: they were born with a full complement of eggs that were gradually used up during reproductive years.
These losses, combined with alterations in hormone production, led to the loss of childbearing capacity by the late 50s.
Not so, say Ji Wu and colleagues from Shanghai Jiao Tong University, who have shown that adult female mice harbor stem cell-like cells in their ovaries that can be coaxed to become fully functional eggs.
“If you are looking to disprove that females cannot make new eggs, this paper proves it. This is the smoking gun,” Jonathan Tilly, a Harvard-based OB/GYN professor told the Washington Post.
The scientists removed ovaries from mice and isolated from them some cells that appeared to be germline stem cells.
They stimulated the cells to differentiate in petri dishes, labeled them with a fluorescent protein and injected them into the ovaries of mice that had been rendered infertile using chemotherapy drugs.
These mice soon became proud mothers to offspring that glowed in the dark proving they had been conceived from the fluorescent labeled eggs.
The offspring were normal in every way, reported the authors in Nature.
The findings raise hope for women who need to delay childbearing or who are facing possible sterilization secondary to surgery or chemotherapy.
Yet some researchers remained cautious, “The aging process of the human egg differs fundamentally from that of the mouse egg,” said David Keefe, an OB/GYN professor at the University of South Florida.
“Except at Disney World, humans are not large mice,” he reminded the Post.