Last year a group of Massachusetts General Hospital (MGH) researchers announced surprising findings that female mice contrary to longstanding theories of mammalian reproductive physiology retained the ability to make new egg cells or oocytes into adulthood. Now the same investigators report new data supporting the earlier research and identifying a potential source for the production of these cells stem cells in the bone marrow. Their article appears in the July 29 issue of Cell.

"We may be ushering in a new era in the clinical management of female infertility and menopause," says Jonathan Tilly, PhD, director of the Vincent Center for Reproductive Biology at MGH and leader of the research team. "This could lead to new treatment approaches based not on drugs but on regenerative medicine through adult stem cells."

The group's 2004 report in Nature contradicted what had been regarded as a dogma of mammalian biology: that females are born with a limited, non-renewable supply of oocytes that are depleted throughout life. Instead the MGH team found evidence that adult female mice are constantly turning over their oocyte supply and producing new oocytes and follicles, the tiny sacs in which eggs grow. The current study was designed to reinforce the earlier findings and also to identify the source of the new oocytes.

In their first experiment, the team injected normal adult female mice with the chemotherapy drug doxorubicin, which is known to be less likely to cause infertility than other anti-cancer drugs. In the first 24 hours after the injections, the mice rapidly lost nearly 80 percent of their oocyte-containing follicles. But their follicles regenerated rapidly, with hundreds appearing over the next 12 to 24 hours. Two months later, ovaries from the treated mice looked identical to those from untreated controls, suggesting that while existing ooc
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Contact: Sue McGreevey
smcgreevey@partners.org
617-724-2764
Massachusetts General Hospital
27-Jul-2005