Rapid accumulation of deleted mitochondrial deoxyribonucleic acid in postmenopausal ovaries

To study the aging process in human ovary, we analyzed the accumulation of mitochondrial DNA (mtDNA) mutation in ovary in women of various ages. Thirty-nine tissues from ovaries and abdominal muscles, ranging from those of a fetus to those of a 77-yr-old woman, were collected at artificial abortion or gynecological surgery. Total DNA was extracted from these tissues, and parts of mtDNA were amplified via polymerase chain reaction. Through these experiments, we found a 4977-bp deletion of mtDNA between the ATPase8 and ND5 genes in ovarian samples obtained from menopausal and postmenopausal women and in all muscle samples. Quantitative analysis of the deleted mtDNA also showed that the accumulation of deleted mtDNA in the ovary occurs rapidly around the menopausal period while the accumulation found in abdominal muscle occurs gradually with aging. These results indicated that the mtDNA deletion occurs in muscular tissues even at very young ages but that accumulation of the deletion in ovarian tissue starts at the menopausal period and may have a relationship to dysfunction of the ovary in aging.