Aging and aneuploidy in human oocytes and follicular cells

The incidence of chromosomal aneuploidy in the oocyte and surrounding follicular cells in women of different ages was investigated. Oocytes and granulosa cells derived from ovarian specimens from a random population of 289 adult patients ages 16 to 76 years undergoing gynecologic surgery for nonovarian pathology were cultured for short periods, and cytogenetic preparations were scored for chromosome number and morphology. Of 91 oocytes harvested at second meiotic metaphase, five oocytes revealed a chromosomal abnormality. Cytogenetic analysis of the granulosa cells revealed aneuploid cells as well as complements with structural changes. A significant difference between the percentage of granulosa cell aneuploidy in the 25 to 34 years group and all other age groups was found, suggesting a decrease of the tendency for granulosa cells to exhibit aneuploidy in older age groups. Previous reports of aneuploidy in human ovary and other somatic cell types suggest that follicular cells behave differently in their response to aging. There also would appear to be a difference between the chromosomal response of oocytes and granulosa cells to aging.