WASHINGTON, Jan. 30 -- Scientists in China and the United States discovered how ovaries age in non-human primates in unprecedented details.

The study published on Thursday in the journal Cell revealed that two genes that could be used as biomarkers and point to therapeutic targets for diagnosing and treating female infertility and age-associated ovarian diseases, such as ovarian cancer, in humans.

The scientists compared 2,601 ovarian cells from young and old non-human primates, and identified gene activity patterns for every type of primate ovarian cell including ooctyes and granulosa cells, which surround the oocytes as they develop.

"Our goal was to analyze each ovarian cell type along with patterns in gene expression in order to better understand exactly how ovaries age," said the paper's co-corresponding author Qu Jing with the Chinese Academy of Sciences. "This systematic approach provides a better understanding of the mechanisms of healthy ovarian aging."

As the primate ovarian cells aged, some of the genes that fight cellular stress became less active which led to damage and impairment in function, according to the study.

The scientists found two key antioxidant genes (IDH1 and NDUFB10) showed decreased function. Also, they tested what happened to the human cells when the antioxidant genes were made non-functional. They found that without the two antioxidant genes, the cells appeared old and similar to the old non-human primate cells.

The results suggest that the two genes represent promising biomarkers or therapeutic targets for the diagnosis and treatment of age-related decline of the ovaries.

"Our results will hopefully lead to the development of new tools to aid in the rejuvenation of aged ovarian cells," said Liu Guanghui with Institute of Biophysics of the Chinese Academy of Sciences.