Discovery promises new fertility treatments, Japan

Main Category: Fertility
Article Date: 07 Sep 2004 - 1:00 PDT


Japanese researchers have succeeded in producing baby mice using oocytes--precursors to mature egg cells--extracted from frozen ovarian tissue and later fertilized and cultivated in vitro.

For women and girls who lose ovarian function due to cancer, the treatment method, a world first, holds out the possibility of becoming pregnant later in life.

The group, which comprises fertility treatment specialists from Kyoto University and Kato Ladies Clinic in Shinjuku Ward, Tokyo, started by removing ovarian tissue from an adult female mouse.

Ovarian tissue contains oocytes, which develop into mature ova, or eggs, after two meiotic divisions--a cell division process that halves the number of chromosomes, producing mature eggs or sperm from precursor cells known as gametocytes. The ovarian tissue was then frozen and stored. Later, some of it was transplanted to the kidney of a different mouse.

After 10 days, a number of immature egg cells that had developed inside the second mouse's kidney were transferred to a test tube and cultivated until they reached maturity. These eggs were then fertilized in vitro, and transferred to the uterus of another mouse. So far, the method has yielded 14 baby mice.

CONTINUES............www.yomiuri.co.jp

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