[Apoptosis of human oocytes is age-related].

OBJECTIVE

To study the morphological characteristics, and rate of apoptosis of human oocytes in relation to age.

METHODS

206 oocytes were aspirated from antral follicles 4-6 mm in diameter from 58 patients who had surgery done for ovarian cysts. These oocytes were incubated in Ham's F10 with 10% fetal cord serum (FCS) for 48-120 hours, and examined under inverted microscope every 6-8 hours to see their morphological changes. In situ end-labeling (ISEL) of fragmented DNA was used to confirm apoptosis.

RESULTS

The characteristics of apoptosis are: (1) shape change of oocytes. (2) oocyte shrinkage. (3) chromatic condensation and apoptotic body formation. (4) internucleosomal DNA cleavage was shown by ISEL. Apoptosis occurred in 13.9% (women aged 21-30), 37.7% (women aged 31-40), and 61.5% (women aged 41-50) respectively. The rate of apoptosis was much higher in women aged 41-50 than that in the other two groups.

CONCLUSION

The rate of apoptosis of human immature oocytes cultured in vitro is much higher in older women aged 41-50 than in those aged 21-40, which may account for the poor response to superovulation stimulation and low oocyte quality in older women.